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1.
Sci Total Environ ; 953: 176113, 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39260510

RESUMEN

Zinc (Zn) deficiency is a global problem disorder affecting both crops and humans. Herein, modified functional carbon nanodots (MFCNs) with various structures and characteristics were developed to regulate tomato yields and Zn migration in plant-soil systems affected by Zn deficiency through structure-function relationships. Sulfur-doped FCNs (S-FCNs), nitrogen-doped FCNs (N-FCNs), and nitrogen­sulfur co-doped FCNs (N,S-FCNs) were hydrothermally modified using FCNs as precursors. Their regulatory effects on tomatoes growing in Zn-deficient alkaline soils were studied in pot culture experiments. Specifically, 8 mg kg-1 of FCNs and S-FCNs improved tomato yields by 132 % and 108 %, respectively, compared with the control. However, N-FCNs and N,S-FCNs showed no significant effect on yield compared with the control (P < 0.05). Moreover, the application of FCNs or S-FCNs significantly improved fruit quality and nutritional value, including Zn content (by 26.3 % and 22.0 %, respectively) and naturally occurring antioxidants (by 3.37- and 2.08-fold for lycopene, 1.31- and 1.18-fold for flavonoids, and 2.28- and 1.89-fold for phenolics, respectively; P < 0.05). Although N-FCNs and N,S-FCNs increased Zn contents, they inhibited the synthesis of naturally occurring antioxidants in fruits. Zn bioaccessibility, uptake, and transportation in plant-soil systems were regulated by MFCNs through both direct and indirect mechanisms, including ionic reactions, plant physiology, and environmental effects. MFCNs regulated plant tolerance to Zn deficiency not only by affecting root activity, redox homeostasis, micronutrient balance, chelator synthesis, genetic expression, and plant photosynthesis but also by influencing rhizosphere soil properties and the microbial environment. Based on their dual role as "plant growth regulators" and "soil conditioners", MFCNs may have general applicability in agriculture. This study highlights the behavior of MFCNs in plant-soil systems, providing innovative nanotools for enhancing Zn availability, crop stress resistance and environmental preservation in sustainable agriculture.

2.
Int J Mol Sci ; 25(17)2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39273279

RESUMEN

The rapid detection of contaminants in water resources is vital for safeguarding the environment, where the use of eco-friendly materials for water monitoring technologies has become increasingly prioritized. In this context, the role of biocomposites in the development of a SERS sensor is reported in this study. Grafted chitosan was employed as a matrix support for Ag nanoparticles (NPs) for the surface-enhanced Raman spectroscopy (SERS). Chitosan (CS) was decorated with thiol and carboxylic acid groups by incorporating S-acetyl mercaptosuccinic anhydride (SAMSA) to yield CS-SAMSA. Then, Ag NPs were immobilized onto the CS-SAMSA (Ag@CS-SAMSA) and characterized by spectral methods (IR, Raman, NIR, solid state 13C NMR with CP-MAS, XPS, and TEM). Ag@CS-SAMSA was evaluated as a substrate for SERS, where methylene blue (MB) was used as a model dye adsorbate. The Ag@CS-SAMSA sensor demonstrated a high sensitivity (with an enhancement factor ca. 108) and reusability over three cycles, with acceptable reproducibility and storage stability. The Raman imaging revealed a large SERS effect, whereas the MB detection varied from 1-100 µM. The limits of detection (LOD) and quantitation (LOQ) of the biocomposite sensor were characterized, revealing properties that rival current state-of-the-art systems. The dye adsorption profiles were studied via SERS by fitting the isotherm results with the Hill model to yield the ΔG°ads for the adsorption process. This research demonstrates a sustainable dual-function biocomposite with tailored adsorption and sensing properties suitable for potential utility in advanced water treatment technology and environmental monitoring applications.


Asunto(s)
Quitosano , Nanopartículas del Metal , Plata , Espectrometría Raman , Quitosano/química , Espectrometría Raman/métodos , Plata/química , Nanopartículas del Metal/química , Límite de Detección , Colorantes/química , Colorantes/análisis , Cationes/análisis , Contaminantes Químicos del Agua/análisis , Azul de Metileno/química
3.
4.
Int J Biol Macromol ; 277(Pt 1): 134130, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39053822

RESUMEN

Allium plants, including garlic, onions, shallots, and leeks, belong to the Alliaceae family and are utilized as vegetable, medicinal, and ornamental plants. These plants are consumed both raw and cooked and are noted in traditional medicine for their antibacterial, antitumor, and diuretic properties. Allium plants are a rich source of polyphenols, organosulfur compounds, flavonoids, alkaloids, and polysaccharides, which contribute to their health benefits. As consumer interest in the association between diet and health grows, there is an increasing market demand for foods that promote health, particularly those rich in dietary fiber or non-starch polysaccharides. Allium polysaccharides (APS) have molecular weights of 1 × 103-1 × 106 Da containing small amounts of pectin, glucofructan, or glycoproteins and large amounts of fructans. APS, despite its complex structure, is one of the principal active components of Allium plants but is often overlooked, which restricts its practical application. This paper provides a comprehensive overview of the extraction and purification, structural and functional characteristics, bioactivities, structure-function relationships, and chemical modifications of APS, as well as the effects of APS processing and storage. Additionally, this paper outlines future research directions for APS, which will inform its development and application in the food, pharmaceutical, and cosmetic industries.


Asunto(s)
Allium , Polisacáridos , Allium/química , Polisacáridos/química , Polisacáridos/farmacología , Humanos , Extractos Vegetales/química , Extractos Vegetales/farmacología , Animales
5.
J Mech Behav Biomed Mater ; 157: 106658, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39018919

RESUMEN

Although the sacroiliac (SI) joint can be a source of lower back and buttock pain, no comprehensive characterization studies on SI cartilage have been conducted. Using the minipig as a large animal model, this study conducted the first biomechanical, biochemical, and histological characterization of SI joint cartilage. Because previous literature has reported that sacral cartilage and iliac cartilage within the SI joint are histologically distinct, concomitantly it was expected that functional properties of the sacral cartilage would differ from those of the iliac cartilage. Creep indentation, uniaxial tension, biochemical, and histological analyses were conducted on the sacral and iliac cartilage of skeletally mature female Yucatan minipigs (n = 6-8 for all quantitative tests). Concurring with prior literature, the iliac cartilage appeared to be more fibrous than the sacral cartilage. Glycosaminoglycan content was 2.2 times higher in the sacral cartilage. The aggregate modulus of the sacral cartilage was 133 ± 62 kPa, significantly higher than iliac cartilage, which only had an aggregate modulus of 51 ± 61 kPa. Tensile testing was conducted in both cranial-caudal and ventral-dorsal axes, and Young's modulus values ranged from 2.5 ± 1.5 MPa to 13.6 ± 1.5 MPa, depending on anatomical structure (i.e., sacral vs. iliac) and orientation of the tensile test. The Young's modulus of sacral cartilage was 5.5 times higher in the cranial-caudal axis and 2.0 times higher in the ventral-dorsal axis than the iliac cartilage. The results indicate that the sacral and iliac cartilages are functionally distinct from each other. Understanding the distinct differences between sacral and iliac cartilage provides insight into the structure and function of the SI joint, which may inform future research aimed at repairing SI joint cartilage.


Asunto(s)
Fenómenos Mecánicos , Articulación Sacroiliaca , Porcinos Enanos , Animales , Porcinos , Fenómenos Biomecánicos , Femenino , Cartílago/fisiología , Cartílago/citología , Ensayo de Materiales , Cartílago Articular/fisiología , Cartílago Articular/citología , Pruebas Mecánicas , Glicosaminoglicanos/metabolismo
6.
BMC Biol ; 22(1): 129, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38822347

RESUMEN

BACKGROUND: The female locust is equipped with unique digging tools, namely two pairs of valves-a dorsal and a ventral-utilized for excavating an underground hole in which she lays her eggs. This apparatus ensures that the eggs are protected from potential predators and provides optimal conditions for successful hatching. The dorsal and the ventral valves are assigned distinct roles in the digging process. Specifically, the ventral valves primarily function as anchors during propagation, while the dorsal valves displace soil and shape the underground tunnel. RESULTS: In this study, we investigated the noticeable asymmetry and distinct shapes of the valves, using a geometrical model and a finite element method. Our analysis revealed that although the two pairs of valves share morphological similarities, they exhibit different 3D characteristics in terms of absolute size and structure. We introduced a structural characteristic, the skew of the valve cross-section, to quantify the differences between the two pairs of valves. Our findings indicate that these structural variations do not significantly contribute to the valves' load-bearing capabilities under external forces. CONCLUSIONS: The evolutionary development of the form of the female locust digging valves is more aligned with fitting their respective functions rather than solely responding to biomechanical support needs. By understanding the intricate features of these locust valves, and using our geometrical model, valuable insights can be obtained for creating more efficient and specialized tools for various digging applications.


Asunto(s)
Saltamontes , Animales , Femenino , Saltamontes/fisiología , Saltamontes/anatomía & histología , Fenómenos Biomecánicos , Análisis de Elementos Finitos
7.
Expert Opin Drug Discov ; 19(7): 855-867, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38803122

RESUMEN

INTRODUCTION: Auranofin (AF) is a well-established, FDA-approved, antiarthritic gold drug that is currently being reevaluated for a variety of therapeutic indications through drug repurposing. AF has shown great promise as a potential anticancer agent and has been approved for a few clinical trials in cancer. The renewed interest in AF has led to extensive research into the design, preparation and biological evaluation of auranofin analogs, which may have an even better pharmacological profile than the parent drug. AREAS COVERED: This article reviews the strategies for chemical modification of the AF scaffold. Several auranofin analogs have been prepared and characterized for medical application in the field of cancer treatment over the last 20 years. Some emerging structure-function relationships are proposed and discussed. EXPERT OPINION: The chemical modification of the AF scaffold has been the subject of intense activity in recent years and this strategy has led to the preparation and evaluation of several AF analogs. The case of iodauranofin is a particularly promising example. The availability of homogeneous biological data for a group of AF derivatives allows some initial structure-function relationships to be proposed, which may inspire the design and synthesis of new and better AF analogs for cancer treatment.


Asunto(s)
Antineoplásicos , Auranofina , Diseño de Fármacos , Neoplasias , Auranofina/farmacología , Humanos , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/síntesis química , Relación Estructura-Actividad , Neoplasias/tratamiento farmacológico , Animales , Reposicionamiento de Medicamentos
8.
Sci Rep ; 14(1): 12463, 2024 05 30.
Artículo en Inglés | MEDLINE | ID: mdl-38816452

RESUMEN

The non-essential amino acid L-serine is involved in a number of metabolic pathways and in the brain its level is largely due to the biosynthesis from the glycolytic intermediate D-3-phosphoglycerate by the phosphorylated pathway (PP). This cytosolic pathway is made by three enzymes proposed to generate a reversible metabolon named the "serinosome". Phosphoserine phosphatase (PSP) catalyses the last and irreversible step, representing the driving force pushing L-serine synthesis. Genetic defects of the PP enzymes result in strong neurological phenotypes. Recently, we identified the homozygous missense variant [NM_004577.4: c.398A > G p.(Asn133Ser)] in the PSPH, the PSP encoding gene, in two siblings with a neurodevelopmental syndrome and a myelopathy. The recombinant Asn133Ser enzyme does not show significant alterations in protein conformation and dimeric oligomerization state, as well as in enzymatic activity and functionality of the reconstructed PP. However, the Asn133Ser variant is less stable than wild-type PSP, a feature also apparent at cellular level. Studies on patients' fibroblasts also highlight a strong decrease in the level of the enzymes of the PP, a partial nuclear and perinuclear localization of variant PSP and a stronger perinuclear aggregates formation. We propose that these alterations contribute to the formation of a dysfunctional serinosome and thus to the observed reduction of L-serine, glycine and D-serine levels (the latter playing a crucial role in modulating NMDA receptors). The characterization of patients harbouring the Asn133Ser PSP substitution allows to go deep into the molecular mechanisms related to L-serine deficit and to suggest treatments to cope with the observed amino acids alterations.


Asunto(s)
Serina , Humanos , Serina/metabolismo , Mutación Missense , Monoéster Fosfórico Hidrolasas/metabolismo , Monoéster Fosfórico Hidrolasas/genética , Fibroblastos/metabolismo , Masculino , Trastornos del Neurodesarrollo/genética , Trastornos del Neurodesarrollo/metabolismo , Femenino
9.
Int J Biol Macromol ; 270(Pt 2): 132281, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38740150

RESUMEN

DapE is a Zn2+-metallohydrolase recognized as a drug target for bacterial control. It is a homodimer that requires the exchange of interface strands by an induced fit essential for catalysis. Identifying novel anti-DapE agents requires greater structural details. Most of the characterized DapEs are from the Gram-negative group. Here, two high-resolution DapE crystal structures from Enterococcus faecium are presented for the first time with novel aspects. A loosened enzyme intermediate between the open and closed conformations is observed. Substrates may bind to loose state, subsequently it closes, where hydrolysis occurs, and finally, the change to the open state leads to the release of the products. Mutation of His352 suggests a role, along with His194, in the oxyanion stabilization in the mono-metalated Zn2+ isoform, while in the di-metalated isoform, the metal center 2 complements it function. An aromatic-π box potentially involved in the interaction of DapE with other proteins, and a peptide flip could determine the specificity in the Gram-positive ArgE/DapE group. Finally, details of two extra-catalytic cavities whose geometry changes depending on the conformational state of the enzyme are presented. These cavities could be a target for developing non-competitive agents that trap the enzyme in an inactive state.


Asunto(s)
Proteínas Bacterianas , Enterococcus faecium , Enterococcus faecium/enzimología , Especificidad por Sustrato , Ligandos , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Modelos Moleculares , Conformación Proteica , Zinc/química , Zinc/metabolismo , Dominio Catalítico , Amidohidrolasas/química , Amidohidrolasas/metabolismo , Amidohidrolasas/genética , Cristalografía por Rayos X , Secuencia de Aminoácidos , Unión Proteica
10.
Arch Biochem Biophys ; 756: 110011, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38649133

RESUMEN

Structure-function relationships are key to understanding enzyme mechanisms, controlling enzyme activities, and designing biocatalysts. Here, we investigate the functions of arginine residues in the active sites of pyridoxal-5'-phosphate (PLP)-dependent non-canonical d-amino acid transaminases, focusing on the analysis of a transaminase from Haliscomenobacter hydrossis. Our results show that the tandem of arginine residues R28* and R90, which form the conserved R-[RK] motif in non-canonical d-amino acid transaminases, not only facilitates effective substrate binding but also regulates the catalytic properties of PLP. Non-covalent interactions between residues R28*, R90, and Y147 strengthen the hydrogen bond between Y147 and PLP, thereby maintaining the reactivity of the cofactor. Next, the R90 residue contributes to the stability of the holoenzyme. Finally, the R90I substitution induces structural changes that lead to substrate promiscuity, as evidenced by the effective binding of substrates with and without the α-carboxylate group. This study sheds light on the structural determinants of the activity of non-canonical d-amino acid transaminases. Understanding the structural basis of the active site plasticity in the non-canonical transaminase from H. hydrossis, which is characterized by effective conversion of d-amino acids and α-keto acids, may help to tailor it for industrial applications.


Asunto(s)
Arginina , Dominio Catalítico , Fosfato de Piridoxal , Transaminasas , Transaminasas/metabolismo , Transaminasas/química , Arginina/química , Arginina/metabolismo , Fosfato de Piridoxal/metabolismo , Fosfato de Piridoxal/química , Especificidad por Sustrato , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Modelos Moleculares
11.
Protein Sci ; 33(4): e4964, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38501584

RESUMEN

Worldwide, tuberculosis is the second leading infectious killer and multidrug resistance severely hampers disease control. Mycolic acids are a unique category of lipids that are essential for viability, virulence, and persistence of the causative agent, Mycobacterium tuberculosis (Mtb). Therefore, enzymes involved in mycolic acid biosynthesis represent an important class of drug targets. We previously showed that the (3R)-hydroxyacyl-ACP dehydratase (HAD) protein HadD is dedicated mainly to the production of ketomycolic acids and plays a determinant role in Mtb biofilm formation and virulence. Here, we discovered that HAD activity requires the formation of a tight heterotetramer between HadD and HadB, a HAD unit encoded by a distinct chromosomal region. Using biochemical, structural, and cell-based analyses, we showed that HadB is the catalytic subunit, whereas HadD is involved in substrate binding. Based on HadBDMtb crystal structure and substrate-bound models, we identified determinants of the ultra-long-chain lipid substrate specificity and revealed details of structure-function relationship. HadBDMtb unique function is partly due to a wider opening and a higher flexibility of the substrate-binding crevice in HadD, as well as the drastically truncated central α-helix of HadD hotdog fold, a feature described for the first time in a HAD enzyme. Taken together, our study shows that HadBDMtb , and not HadD alone, is the biologically relevant functional unit. These results have important implications for designing innovative antivirulence molecules to fight tuberculosis, as they suggest that the target to consider is not an isolated subunit, but the whole HadBD complex.


Asunto(s)
Mycobacterium tuberculosis , Tuberculosis , Humanos , Acido Graso Sintasa Tipo II/química , Ácidos Micólicos/metabolismo , Hidroliasas/química
12.
Res Sq ; 2024 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-38464189

RESUMEN

Mutations in human isocitrate dehydrogenase 1 (IDH1) drive tumor formation in a variety of cancers by replacing its conventional activity with a neomorphic activity that generates an oncometabolite. Little is understood of the mechanistic differences among tumor-driving IDH1 mutants. We previously reported that the R132Q mutant uniquely preserves conventional activity while catalyzing robust oncometabolite production, allowing an opportunity to compare these reaction mechanisms within a single active site. Here, we employed static and dynamic structural methods and found that, compared to R132H, the R132Q active site adopted a conformation primed for catalysis with optimized substrate binding and hydride transfer to drive improved conventional and neomorphic activity over R132H. This active site remodeling revealed a possible mechanism of resistance to selective mutant IDH1 therapeutic inhibitors. This work enhances our understanding of fundamental IDH1 mechanisms while pinpointing regions for improving inhibitor selectivity.

13.
Int J Biol Macromol ; 264(Pt 2): 130731, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38471615

RESUMEN

Natural biopolymers derived from exopolysaccharides (EPSs) are considered eco-friendly and sustainable alternatives to available traditional synthetic counterparts. Salt-tolerant bacteria inhabiting harsh ecological niches have evolved a number of unique adaptation strategies allowing them to maintain cellular integrity and assuring their long-term survival; among these, producing EPSs can be adopted as an effective strategy to thrive under high-salt conditions. A great diversity of EPSs from salt-tolerant bacteria have attracted widespread attention recently. Because of factors such as their unique structural, physicochemical, and functional characteristics, EPSs are commercially valuable for the global market and their application potential in various sectors is promising. However, large-scale production and industrial development of these biopolymers are hindered by their low yields and high costs. Consequently, the research progress and future prospects of salt-tolerant bacterial EPSs must be systematically reviewed to further promote their application and commercialization. In this review, the structure and properties of EPSs produced by a variety of salt-tolerant bacterial strains isolated from different sources are summarized. Further, feasible strategies for solving production bottlenecks are discussed, which provides a scientific basis and direct reference for more scientific and rational EPS development.


Asunto(s)
Halobacteriaceae , Polisacáridos Bacterianos , Polisacáridos Bacterianos/química , Bacterias , Biopolímeros
14.
Elife ; 122024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38271216

RESUMEN

The neurotransmitter:sodium symporters (NSSs) are secondary active transporters that couple the reuptake of substrate to the symport of one or two sodium ions. One bound Na+ (Na1) contributes to the substrate binding, while the other Na+ (Na2) is thought to be involved in the conformational transition of the NSS. Two NSS members, the serotonin transporter (SERT) and the Drosophila dopamine transporter (dDAT), also couple substrate uptake to the antiport of K+ by a largely undefined mechanism. We have previously shown that the bacterial NSS homologue, LeuT, also binds K+, and could therefore serve as a model protein for the exploration of K+ binding in NSS proteins. Here, we characterize the impact of K+ on substrate affinity and transport as well as on LeuT conformational equilibrium states. Both radioligand binding assays and transition metal ion FRET (tmFRET) yielded similar K+ affinities for LeuT. K+ binding was specific and saturable. LeuT reconstituted into proteoliposomes showed that intra-vesicular K+ dose-dependently increased the transport velocity of [3H]alanine, whereas extra-vesicular K+ had no apparent effect. K+ binding induced a LeuT conformation distinct from the Na+- and substrate-bound conformation. Conservative mutations of the Na1 site residues affected the binding of Na+ and K+ to different degrees. The Na1 site mutation N27Q caused a >10-fold decrease in K+ affinity but at the same time a ~3-fold increase in Na+ affinity. Together, the results suggest that K+ binding to LeuT modulates substrate transport and that the K+ affinity and selectivity for LeuT is sensitive to mutations in the Na1 site, pointing toward the Na1 site as a candidate site for facilitating the interaction with K+ in some NSSs.


Asunto(s)
Sodio , Simportadores , Sodio/metabolismo , Proteínas de Transporte de Neurotransmisores en la Membrana Plasmática/metabolismo , Simportadores/metabolismo , Sitios de Unión , Neurotransmisores
15.
Int J Biol Macromol ; 259(Pt 1): 129226, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38184030

RESUMEN

In higher eukaryotes and plants, the last two sequential steps in the de novo biosynthesis of uridine 5'-monophosphate (UMP) are catalyzed by a bifunctional natural chimeric protein called UMP synthase (UMPS). In higher plants, UMPS consists of two naturally fused enzymes: orotate phosphoribosyltransferase (OPRTase) at N-terminal and orotidine-5'-monophosphate decarboxylase (ODCase) at C-terminal. In this work, we obtained the full functional recombinant protein UMPS from Coffea arabica (CaUMPS) and studied its structure-function relationships. A biochemical and structural characterization of a plant UMPS with its two functional domains is described together with the presentation of the first crystal structure of a plant ODCase at 1.4 Å resolution. The kinetic parameters measured of CaOPRTase and CaODCase domains were comparable to those reported. The crystallographic structure revealed that CaODCase is a dimer that conserves the typical fold observed in other ODCases from prokaryote and eukaryote with a 1-deoxy-ribofuranose-5'-phosphate molecule bound in the active site of one subunit induced a closed conformation. Our results add to the knowledge of one of the key enzymes of the de novo biosynthesis of pyrimidines in plant metabolism and open the door to future applications.


Asunto(s)
Carboxiliasas , Coffea , Orotato Fosforribosiltransferasa/química , Orotato Fosforribosiltransferasa/metabolismo , Orotidina-5'-Fosfato Descarboxilasa/genética , Orotidina-5'-Fosfato Descarboxilasa/química , Orotidina-5'-Fosfato Descarboxilasa/metabolismo , Complejos Multienzimáticos/química , Proteínas Recombinantes/genética , Uridina Monofosfato
16.
bioRxiv ; 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38260668

RESUMEN

Mutations in human isocitrate dehydrogenase 1 (IDH1) drive tumor formation in a variety of cancers by replacing its conventional activity with a neomorphic activity that generates an oncometabolite. Little is understood of the mechanistic differences among tumor-driving IDH1 mutants. We previously reported that the R132Q mutant uniquely preserves conventional activity while catalyzing robust oncometabolite production, allowing an opportunity to compare these reaction mechanisms within a single active site. Here, we employed static and dynamic structural methods and found that, compared to R132H, the R132Q active site adopted a conformation primed for catalysis with optimized substrate binding and hydride transfer to drive improved conventional and neomorphic activity over R132H. This active site remodeling revealed a possible mechanism of resistance to selective mutant IDH1 therapeutic inhibitors. This work enhances our understanding of fundamental IDH1 mechanisms while pinpointing regions for improving inhibitor selectivity.

17.
JOR Spine ; 7(1): e1289, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38222810

RESUMEN

Lumbar intervertebral disc herniation, as a leading cause of low back pain, productivity loss, and disability, is a common musculoskeletal disorder that results in significant socioeconomic burdens. Despite extensive clinical and basic scientific research efforts, herniation etiopathogenesis, particularly its initiation and progression, is not well understood. Understanding herniation etiopathogenesis is essential for developing effective preventive measures and therapeutic interventions. Thus, this review seeks to provide a thorough overview of the advances in herniation-oriented research, with a discussion on ongoing challenges and potential future directions for clinical, translational, and basic scientific investigations to facilitate innovative interdisciplinary research aimed at understanding herniation etiopathogenesis. Specifically, risk factors for herniation are identified and summarized, including familial predisposition, obesity, diabetes mellitus, smoking tobacco, selected cardiovascular diseases, disc degeneration, and occupational risks. Basic scientific experimental and computational research that aims to understand the link between excessive mechanical load, catabolic tissue remodeling due to inflammation or insufficient nutrient supply, and herniation, are also reviewed. Potential future directions to address the current challenges in herniation-oriented research are explored by combining known progressive development in existing research techniques with ongoing technological advances. More research on the relationship between occupational risk factors and herniation, as well as the relationship between degeneration and herniation, is needed to develop preventive measures for working-age individuals. Notably, researchers should explore using or modifying existing degeneration animal models to study herniation etiopathogenesis, as such models may allow for a better understanding of how to prevent mild-to-moderately degenerated discs from herniating.

18.
Int J Mol Sci ; 24(22)2023 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-38003383

RESUMEN

Enzymes with expanded substrate specificity are good starting points for the design of biocatalysts for target reactions. However, the structural basis of the expanded substrate specificity is still elusive, especially in the superfamily of pyridoxal-5'-phosphate-dependent transaminases, which are characterized by a conserved organization of both the active site and functional dimer. Here, we analyze the structure-function relationships in a non-canonical D-amino acid transaminase from Blastococcus saxobsidens, which is active towards D-amino acids and primary (R)-amines. A detailed study of the enzyme includes a kinetic analysis of its substrate scope and a structural analysis of the holoenzyme and its complex with phenylhydrazine-a reversible inhibitor and analogue of (R)-1-phenylethylamine-a benchmark substrate of (R)-selective amine transaminases. We suggest that the features of the active site of transaminase from B. saxobsidens, such as the flexibility of the R34 and R96 residues, the lack of bulky residues in the ß-turn at the entrance to the active site, and the short O-pocket loop, facilitate the binding of substrates with and without α-carboxylate groups. The proposed structural determinants of the expanded substrate specificity can be used for the design of transaminases for the stereoselective amination of keto compounds.


Asunto(s)
Aminoácidos , Transaminasas , Transaminasas/metabolismo , Especificidad por Sustrato , Cinética , Fenetilaminas/metabolismo
19.
ChemMedChem ; 18(24): e202300328, 2023 12 14.
Artículo en Inglés | MEDLINE | ID: mdl-37874976

RESUMEN

Antimicrobial resistance (AMR) interferes with the effective treatment of infections and increases the risk of microbial spread and infection-related illness and death. The synergistic activities of combinations of antimicrobial compounds offer satisfactory approaches to some extent. Structurally diverse naphthoquinones (NQs) including menadione (-CH3 group at C2) exhibit substantial antimicrobial activities against multidrug-resistant (MDR) pathogens. We explored the combinations of menadione with antibiotic ciprofloxacin or ampicillin against Staphylococcus aureus and its biofilms. We found an additive (0.590 %) were also observed. However, preformed biofilms were not affected. Dent formation was also evident in S. aureus treated with the test compounds. The structure-function relationship (SFR) of NQs was used to determine and predict their activity pattern against pathogens. Analysis of 10 structurally distinct NQs revealed that the compounds with -Cl, -Br, -CH3 , or -OH groups displayed the lowest MICs (32-256 µg/mL). Furthermore, 1,4-NQs possessing a halogen or -CH3 moiety showed elevated ROS activity, whereas molecules with an -OH group affected cell integrity. Improved activity of antimicrobial combinations and SFR approaches are significant in antimicrobial therapies.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Naftoquinonas , Infecciones Estafilocócicas , Humanos , Antibacterianos/farmacología , Staphylococcus aureus , Vitamina K 3/farmacología , Naftoquinonas/farmacología , Especies Reactivas de Oxígeno , Ampicilina/farmacología , Ciprofloxacina/farmacología , Pruebas de Sensibilidad Microbiana , Biopelículas
20.
Foods ; 12(17)2023 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-37685165

RESUMEN

A greater understanding of protein functionality and its impact on processing and end-product quality is critical for the success of the fast-growing market for plant-based meat products. In this research, simple criteria were developed for categorizing plant proteins derived from soy, yellow pea, and wheat as cold swelling (CS) or heat swelling (HS) through various raw-material tests, including the water absorption index (WAI), least gelation concentration (LGC), rapid visco analysis (RVA), and % protein solubility. These proteins were blended together in different cold-swelling: heat-swelling ratios (0:100 to 90:10 or 0-90% CS) and extruded to obtain texturized vegetable proteins (TVPs). In general, the WAI (2.51-5.61 g/g) and protein solubility (20-46%) showed an increasing trend, while the LGC decreased from 17-18% to 14-15% with an increase in the % CS in raw protein blends. Blends with high CS (60-90%) showed a clear RVA cold viscosity peak, while low-CS (0-40%) blends exhibited minimal swelling. The extrusion-specific mechanical energy for low-CS blends (average 930 kJ/kg) and high-CS blends (average 949 kJ/kg) was similar, even though both were processed with similar in-barrel moisture, but the former had substantially lower protein content (69.7 versus 76.6%). Extrusion led to the aggregation of proteins in all treatments, as seen from the SDS-PAGE and SEC-HPLC analyses, but the protein solubility decreased the most for the high-CS (60-90%) blends as compared to the low-CS (0-40%) blends. This indicated a higher degree of crosslinking due to extrusion for high CS, which, in turn, resulted in a lower extruded TVP bulk density and higher water-holding capacity (average 187 g/L and 4.2 g/g, respectively) as compared to the low-CS treatments (average 226 g/L and 2.9 g/g, respectively). These trends matched with the densely layered microstructure of TVP with low CS and an increase in pores and a spongier structure for high CS, as observed using optical microscopy. The microstructure, bulk density, and WHC observations corresponded well with texture-profile-analysis (TPA) hardness of TVP patties, which decreased from 6949 to 3649 g with an increase in CS from 0 to 90%. The consumer test overall-liking scores (9-point hedonic scale) for TVP patties were significantly lower (3.8-5.1) as compared to beef hamburgers (7.6) (p < 0.05). The data indicated that an improvement in both the texture and flavor of the former might result in a better sensory profile and greater acceptance.

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