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1.
Asian J Psychiatr ; 102: 104242, 2024 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-39305768

RESUMEN

Psychedelic drug therapy has gained prominence for its potential in treating various mental health conditions, including depression, post-traumatic stress disorder (PTSD), and anxiety. Psychedelic treatment differs from conventional psychiatric approaches in mode of action, legal status, and treatment approach. This work delves into the therapeutic potential, mechanisms, and regulatory approvals of key psychedelic substances like psilocybin, 3,4-Methyl enedioxy methamphetamine (MDMA), mescaline, ketamine, and Lysergic acid diethylamide (LSD). It also provides an overview of legal aspects, and regulations surrounding psychedelics in the US & Europe, emphasizing their Schedule I classification due to potential misuse. The United States Food & Drug Administration (USFDA) closely monitors psychedelics, employing expedited pathways for evaluation. Further, recent guidance from the FDA on considerations for clinical Investigations supports the safe development of psychedelics for human welfare. European Medicines Agency (EMA) regulators focus on atypical psychedelics, addressing challenges in safety and efficacy. Marketed products, such as Spravato nasal spray, face limited distribution due to safety concerns. The call for careful regulation and legislation is essential for harnessing psychedelics' potential for therapeutic benefits and human welfare.

2.
Biophys Rep ; 10(4): 201-212, 2024 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-39281198

RESUMEN

Sedimentation solid-state NMR is a novel method for sample preparation in solid-state NMR (ssNMR) studies. It involves the sedimentation of soluble macromolecules such as large protein complexes. By utilizing ultra-high centrifugal forces, the molecules in solution are driven into a high-concentrated hydrogel, resulting in a sample suitable for solid-state NMR. This technique has the advantage of avoiding the need for chemical treatment, thus minimizing the loss of sample biological activity. Sediment ssNMR has been successfully applied to a variety of non-crystalline protein solids, significantly expanding the scope of solid-state NMR research. In theory, using this method, any biological macromolecule in solution can be transferred into a sedimented solute appropriate for solid-state NMR analysis. However, specialized equipment and careful handling are essential for effectively collecting and loading the sedimented solids to solid-state NMR rotors. To improve efficiency, we have designed a series of loading tools to achieve the loading process from the solution to the rotor in one step. In this paper, we illustrate the sample preparation process of sediment NMR using the H1.4-NCP167 complex, which consists of linker histone H1.4 and nucleosome core particle, as an example.

3.
J Psychopharmacol ; : 2698811241278769, 2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39282928

RESUMEN

BACKGROUND: The applications of psilocybin, derived from 'magic mushrooms,' are vast, including a burgeoning practice known as microdosing, which refers to the administration of sub-hallucinogenic doses of psychedelic substances to obtain benefits without experiencing significant cognitive and perceptual distortion. However, current research is fairly new with several limitations and gaps that hinder adequate conclusions on its efficacy. AIMS: This semi-structured review aimed to identify and highlight research gaps in the field of psilocybin microdosing for future research. METHODS: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses based strategy was employed, utilizing a chain of keywords and key phrases across multiple databases, augmented by a cross-sectional Google search for relevant grey literature in the form of the top 10 search results. A total of 40 studies and 8 unique websites were identified, summarized and tabulated into four distinct categories, namely non-clinical, clinical, observational and anecdotal evidence. RESULTS: The majority of available evidence originates from observational studies, while non-clinical and clinical study findings remain comparatively sparse and inconsistent. Web-based findings were consistent with current research findings. Key research gaps were highlighted: the imperative for more randomized placebo-controlled trials, exploration of dose-response ranges, psychological and personality testing of participants, utilization of active placebos, greater diversity in study populations, an increase in psilocybin-exclusive microdosing studies and the refinement of animal models. CONCLUSION: Definitive conclusions regarding the efficacy of psilocybin microdosing remain elusive, emphasizing the need for further study. Numerous research gaps necessitate consideration for future investigations.

4.
JMIR Res Protoc ; 13: e55290, 2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39283663

RESUMEN

BACKGROUND: Helminths are a major global health issue, impacting health, educational, and socioeconomic outcomes. Infections, often starting in childhood, are linked to anemia, malnutrition, cognitive deficit, and in chronic cases of Opisthorchis viverrini (OV), cholangiocarcinoma. The main control strategy for helminth infection is mass drug administration; however, this does not prevent reinfection. As such, prevention strategies are needed. The "Magic Glasses" is a school-based cartoon health education package that has demonstrated success in improving knowledge, attitudes, and practices (KAP) surrounding soil-transmitted helminths (STH) in China and the Philippines. This study is designed to assess the acceptability and impact of the 2 new versions of the Magic Glasses targeting STH and OV designed for the Lower Mekong audience in Cambodia, Lao People's Democratic Republic (PDR), and Thailand. OBJECTIVE: The objective of this study is to evaluate the acceptability of the "Magic Glasses Lower Mekong" and "Magic Glasses Opisthorchiasis" education packages among schoolchildren in the Lower Mekong Basin, and the impact of these education packages on students' KAP surrounding STH and OV, respectively. METHODS: Schoolchildren will be recruited into a cluster randomized controlled trial with intervention and control arms in rural schools in Cambodia, Lao PDR, and Thailand. Schoolchildren's initial acceptability of the intervention will be evaluated using an adapted questionnaire. Sustained acceptability will be assessed at 9-month follow-up through focus group discussions with students and interviews with teachers. Impact will be evaluated by KAP questionnaires on STH and OV. KAP questionnaires will be administered to children at baseline and at follow-up. Indirect impact on parents' KAP of OV and STH will be assessed through focus group discussions at follow-up. RESULTS: The trial is in progress in Lao PDR and Thailand and is expected to commence in Cambodia in January 2024. The results of the study are expected to be available 18 months from the start of recruitment. We hypothesize that participants enrolled in the intervention arm of the study will have higher KAP scores for STH and OV, compared with the participants in the control arm at follow-up. We expect that students will have initial and sustained acceptability of these intervention packages. CONCLUSIONS: This trial will examine the acceptability of the "Magic Glasses Opisthorchiasis" and "Magic Glasses Lower Mekong" interventions and provide evidence on the effectiveness of the "Magic Glasses" on KAP related to OV and STH among schoolchildren in the Lower Mekong Basin. Study results will provide insight on acceptability and impact indicators and inform a scaling up protocol for the "Magic Glasses" education packages in Cambodia, Lao PDR, and Thailand. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12623000271606; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=385315&isReview=true. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/55290.


Asunto(s)
Educación en Salud , Conocimientos, Actitudes y Práctica en Salud , Opistorquiasis , Humanos , Niño , Opistorquiasis/prevención & control , Opistorquiasis/epidemiología , Opistorquiasis/psicología , Cambodia/epidemiología , Laos/epidemiología , Educación en Salud/métodos , Tailandia/epidemiología , Femenino , Masculino , Adolescente , Estudiantes/psicología , Helmintiasis/prevención & control , Helmintiasis/epidemiología , Animales , Dibujos Animados como Asunto
5.
J Psychoactive Drugs ; : 1-13, 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39257234

RESUMEN

Psilocybin, a major indole alkaloid found in magic mushrooms (Psilocybe cubensis), has recently drawn attention as a breakthrough therapy to treat major depressive disorder. This review aimed to summarize and identify knowledge gaps concerning their pharmacokinetic characteristics of psilocybin and its active metabolite, psilocin. Original studies related to pharmacokinetics of psilocybin conducted in vitro, animals, and humans were systematically collected from PubMed, Scopus, and ScienceDirect, from their inceptions to November 2023. Twenty articles were included in this work and assessed for study quality. A comprehensive review of the pharmacokinetics of psilocybin and psilocin in both animals and humans was performed. Psilocybin is considered a prodrug that is dephosphorylated to psilocin by alkaline phosphatase. Following ingestion, the peak psilocin plasma and brain levels were rapidly achieved in a dose-dependent manner. Psilocin is metabolized primarily through both Phase I and Phase II processes with the half-life of 2-3 hours. This review also identified lack of some pharmacokinetic related information and limitations of available research that may help direct future investigations to better understand the pharmacokinetics and improve study design including dose selection and dosage optimization.

6.
ACS Nano ; 2024 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-39234998

RESUMEN

Isomerization, the process by which a molecule is coherently transformed into another molecule with the same molecular formula but a different atomic structure, is an important and well-known phenomenon of organic chemistry, but has only recently been observed for inorganic nanoclusters. Previously, CdS nanoclusters were found to isomerize between two end point structures rapidly and reversibly (the α-phase and ß-phase), mediated by hydroxyl groups on the surface. This observation raised many significant structural and pathway questions. One critical question is why no intermediate states were observed during the isomerization; it is not obvious why an atomic cluster should only have two stable end points rather than multiple intermediate arrangements. In this study, we report that the use of amide functional groups can stabilize intermediate phases during the transformation of CdS magic-size clusters between the α-phase and the ß-phase. When treated with amides in organic solvents, the amides not only facilitate the α-phase to ß-phase isomerization but also exhibit three distinct excitonic features, which we call the ß340-phase, ß350-phase, and ß367-phase. Based on pair distribution function analysis, these intermediates strongly resemble the ß-phase structure but deviate greatly from the α-phase structure. All phases (ß340-phase, ß350-phase, and ß367-phase) have nearly identical structures to the ß-phase, with the ß340-phase having the largest deviation. Despite these intermediates having similar atomic structures, they have up to a 583 meV difference in band gap compared to the ß-phase. Kinetic studies show that the isomers and intermediates follow a traditional progression in the thermodynamic stability of ß340-phase/ß350-phase < α-phase < ß367-phase < ß-phase. The solvent identity and polarity play a crucial role in kinetically arresting these intermediates. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy studies paired with simple density functional theory calculations reveal that the likely mechanism is due to the multifunctional nature of the amides that form an amphoteric surface binding bond motif, which promotes a change in the carboxylic acid binding mode. This change from chelating binding modes to bridging binding modes initiates the isomerization. We propose that the carbonyl group is responsible for the direct interaction with the surface, acting as an L-type ligand which then pulls electron density away from the electron-poor nitrogen site, enabling them to interact with the carboxylate ligands and initiate the change in the binding mode. The isomerization of CdS nanoclusters continues to be a topic of interest, giving insight into fundamental nanoscale chemistry and physics.

7.
Eur J Radiol ; 179: 111666, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39128250

RESUMEN

OBJECTIVE: MAGnetic resonance Imaging Compilation (MAGiC) is typical method of synthetic magnetic resonance imaging (MRI). The present aimed to investigate the role of MAGiC parameters of relaxation time (T1), transverse relaxation time (T2) and proton density (PD) to predict the treatment efficacy of breast cancer patients after neoadjuvant chemotherapy (NAC). METHODS: The present prospective cohort study enrolled 120 breast cancer patients who received NAC during 2021-2023. Demographic data and clinical characteristics including tumor node metastasis (TNM) stage, pathological type, molecular classification and lymph node metastasis were collected. The levels of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) were measured. Patients were divided by treatment efficacy using the Miller-Payne grading as partial pathological response (pPR) group and pathological complete response (pCR). The values of MAGiC parameters of longitudinal T1, T2, and PD values were recorded. RESULTS: In all 120 patients, 73 (60.83%) cases were with pPR and 47 (39.17%) cases were with pCR after treatment. T2 values were markedly lower in pPR patients compared with pCR patients. However, no significant difference was found for T1 and PD values. No significant correlation was observed between any of MAGiC parameters and HER-2, ER or PR. ROC curve showed T2 could be used for prediction of pPR with AUC 0.780. Lymph node metastasis and low levels of T2 were found as independent risk factors for pPR after treatment. CONCLUSION: The T2 value parameter from MAGiC is an independent risk factor for pPR following NAC in breast cancer patients, suggesting its potential as a biomarker for predicting treatment efficacy.


Asunto(s)
Neoplasias de la Mama , Imagen por Resonancia Magnética , Terapia Neoadyuvante , Humanos , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/tratamiento farmacológico , Femenino , Terapia Neoadyuvante/métodos , Persona de Mediana Edad , Imagen por Resonancia Magnética/métodos , Estudios Prospectivos , Adulto , Resultado del Tratamiento , Quimioterapia Adyuvante , Anciano , Estudios de Cohortes , Valor Predictivo de las Pruebas
8.
J Magn Reson ; 367: 107747, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39178749

RESUMEN

The development of magic angle spinning (MAS) at rates ranging from 30 kHz to greater than 100 kHz has substantially advanced solid-state nuclear magnetic resonance (SSNMR) spectroscopy 1H-detection methods. The small rotors required for such MAS rates have a limited sample volume and low 13C-detection sensitivity, rendering the traditional set of standard compounds for SSNMR insufficient or highly inconvenient for shimming and magic-angle calibration. Additionally, the reproducibility of magic angle setting, chemical shift referencing, and probe position can be especially critical for SSNMR experiments at high fields. These conditions suggest the need for a high signal-to-noise ratio (SNR) 1H-detection standard compound, which is preferably multi-purpose, to simplify instrument set up for ultra-fast MAS SSNMR instruments at high magnetic fields. In this study, we present the results for setting magic angle and shimming using tetrakis(trimethylsilyl)silane (TTMSS, or TKS), a tetramethylsilane (TMS) analogue, at near 40 kHz and demonstrate that we can achieve favorable results in less time but with equal or superior precision as traditional KBr and adamantane standards. The high SNR and TMS-like chemical shift of TKS also opens the possibilities for using TKS as an internal standard with biological samples. A single rotor containing a four-component mixture of TKS, adamantane, uniformly 13C, 15N-labeled N-acetyl valine and KBr was used to perform a complete configuration and calibration of a SSNMR probe without sample changes. We anticipate TKS as a standard compound to be especially effective at very high MAS conditions and to greatly simplify the instrument set up for high and ultra-high field SSNMR instruments.

9.
Beilstein J Nanotechnol ; 15: 1010-1016, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39136042

RESUMEN

Electronic and structural properties of calcium clusters with a varying size range of 2-20 atoms are studied using a two-step scheme within the GW and density functional theory (DFT) with generalized gradient approximation (GGA). The GGA overestimates the binding energies, optimized geometries, electron affinities, and ionization potentials reported in the benchmark. The ground-state structure geometry and binding energy were obtained from the DFT for the ground-state structure of each cluster. The binding energy of the neutral clusters of the calcium series follows an increasing trend, except for a few stable even and odd clusters. The electronic properties of the calcium cluster were studied with an all-electron FHI-aims code. In the G 0 W 0 calculation, the magic cluster Ca10 has relatively high ionization potential and low electron affinity. The obtained ionization potentials from the G 0 W 0 @PBE calculation showed that the larger cluster has less variation, whereas the electron affinities of the series have an increasing trend. The ionization potentials from the G 0 W 0 benchmark for the calcium cluster series have not yet been described in the literature.

10.
Chemphyschem ; : e202400537, 2024 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-39129653

RESUMEN

Noncovalent interactions are the basis for a large number of chemical and biological molecular-recognition processes, such as those occurring in supramolecular chemistry, catalysis, solid-state reactions in mechanochemistry, protein folding, protein-nucleic acid binding, and biomolecular phase separation processes. In this perspective article, some recent developments in probing noncovalent interactions by proton-detected solid-state Nuclear Magnetic Resonance (NMR) spectroscopy at Magic-Angle Spinning (MAS) frequencies of 100 kHz and more are reviewed. The development of MAS rotors with decreasing outer diameters, combined with the development of superconducting magnets operating at high static magnetic-field strengths up to 28.2 T (1200 MHz proton Larmor frequency) improves resolution and sensitivity in proton-detected solid-state NMR, which is the fundamental requirement for shedding light on noncovalent interactions in solids. The examples reported in this article range from protein-nucleic acid binding in large ATP-fueled motor proteins to a hydrogen-π interaction in a calixarene-lanthanide complex.

11.
Natl Sci Rev ; 11(8): nwae222, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39210988

RESUMEN

The multiparent advanced generation intercross (MAGIC) population is characterized with great potentials in power and resolution of quantitative trait locus (QTL) mapping, but single nucleotide polymorphism (SNP)-based GWAS does not fully reach its potential. In this study, a MAGIC population of 1021 lines was developed from four Xian and four Geng varieties from five subgroups of rice. A total of 44 000 genes showed functional polymorphisms among eight parents, including frameshift variations or premature stop codon variations, which provides the potential to map almost all genes of the MAGIC population. Principal component analysis results showed that the MAGIC population had a weak population structure. A high-density bin map of 24 414 bins was constructed. Segregation distortion occurred in the regions possessing the genes underlying genetic incompatibility and gamete development. SNP-based association analysis and bin-based linkage analysis identified 25 significant loci and 47 QTLs for heading date, including 14 known heading date genes. The mapping resolution of genes is dependent on genetic effects with offset distances of <55 kb for major effect genes and <123 kb for moderate effect genes. Four causal variants and noncoding structure variants were identified to be associated with heading date. Three to four types of alleles with strong, intermediate, weak, and no genetic effects were identified from eight parents, providing flexibility for the improvement of rice heading date. In most cases, japonica rice carries weak alleles, and indica rice carries strong alleles and nonfunctional alleles. These results confirm that the MAGIC population provides the exceptional opportunity to detect QTLs, and its use is encouraged for mapping genes and mining favorable alleles for breeding.

12.
ACS Nano ; 18(33): 22208-22219, 2024 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-39115283

RESUMEN

We investigate the early stages of cesium lead bromide perovskite formation through absorption spectroscopy of stopped-flow reactions, high-throughput mapping, and direct synthesis and titration of potential precursor species. Calorimetric and spectroscopic measurements of lead bromide complex titrations combined with theoretical calculations suggest that bromide complexes with higher coordination numbers than previously considered for nonpolar systems can better explain observed behaviors. Synthesis mapping of binary lead halides reveals multiple lead bromide species with absorption peaks higher than 300 nm, including a previously observed species with a peak at 313 nm and two species with peaks at 345 and 370 nm that also appear as reaction intermediates during the formation of lead bromide perovskites. Based on theoretical calculations of excitonic energies that match within 50 meV, we give a preliminary assignment of these species as two-dimensional magic-sized clusters with side lengths of 2, 3, and 4 unit cells. Kinetic measurements of the conversion of benzoyl bromide precursor are connected to stopped-flow measurements of product formation and demonstrate that the formation of complexes and magic-sized clusters (i.e., nucleation) is controlled by precursor decomposition, whereas the growth rate of 2D and 3D perovskites is significantly slower.

13.
Front Plant Sci ; 15: 1410851, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39145196

RESUMEN

Multi-parent populations (MPPs) are attractive for genetic and breeding studies because they combine genetic diversity with an easy-to-control population structure. Most methods for mapping QTLs in MPPs focus on the detection of QTLs in single environments. Little attention has been given to mapping QTLs in multienvironment trials (METs) and to detecting and modeling QTL-by-environment interactions (QEIs). We present mixed model approaches for the detection and modeling of consistent versus environment-dependent QTLs, i.e., QTL-by-environment interaction (QEI). QTL effects are assumed to be normally distributed with variances expressing consistency or dependence on environments and families. The entries of the corresponding design matrices are functions of identity-by-descent (IBD) probabilities between parents and offspring and follow from the parental origin of offspring DNA. A polygenic effect is added to the models to account for background genetic variation. We illustrate the wide applicability of our method by analyzing several public MPP datasets with observations from METs. The examples include diallel, nested association mapping (NAM), and multi-parent advanced inter-cross (MAGIC) populations. The results of our approach compare favorably with those of previous studies that used tailored methods.

14.
Artículo en Inglés | MEDLINE | ID: mdl-39019714

RESUMEN

The magic number, or number of ranks needed to achieve a greater than 90 % chance of matching, has not been investigated for diagnostic radiology (DR). Somewhat reflective of a field's changing competitiveness, this individual metric can be useful for reassuring applicants or identifying a need to reach out to mentors. The NRMP's Charting Outcomes in the Match was accessed over the previous 10 cycles to assess changes to magic number and other match-related metrics. Over the last 10 cycles, there has been an increase in magic number for prospective radiologists. Based on the most 2022 recent report, the magic number was 14 compared to 5 and 2 in 2014 and 2016 respectively. Compared to the average US MD senior, those applying into DR were significantly more likely to match in 2014, 2016 and 2020 (p < 0.01 for all), and significantly less likely to match in 2018 and 2022 (p = 0.03 and p < 0.01, respectively). This trend has had important consequences for applicants and programs as the incentive to apply more widely grows. The increasing magic number demonstrates increasing competitiveness in the field, which might be due to a positive job market, changing medical student preferences, or increased access to radiology electives and mentors. The 2024 Charting Outcomes document will be the first to include data from a class almost entirely affected by the change to a pass/fail Step1 and the new preference signaling supplement. It is currently unclear how either change will affect the overall competitiveness of the field and the magic number.

15.
Small Methods ; : e2400622, 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-39021326

RESUMEN

Lipid nanoparticles (LNPs) are increasingly finding applications in targeted drug delivery, including for subcutaneous, intravenous, inhalation, and vaccine administration. While a variety of microscopy techniques are widely used for LNP characterization, their resolution does not allow for characterization of the spatial organization of different components, such as the excipients, targeting agents, or even the active ingredient. Herein, an approach is presented to probe the spatial organization of individual constituent groups of LNPs used for siRNA-based drug delivery, currently in clinical trials, by multinuclear solid-state magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy. Dynamic nuclear polarization is exploited (DNP) for sensitivity enhancement, together with judicious 2H labeing, to detect functionally important LNP constituents, the siRNA and the targeting agent (<1-2 w/v%), respectively, and achieve a structural model of the LNP locating the siRNA in the core, the targeting agent below the surface, and the sugars above the lipid bilayer at the surface. The integrated approach presented here is applicable for structural analysis of LNPs and can be extended more generally to other multi-component biological formulations.

16.
Biomol NMR Assign ; 2024 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-38951472

RESUMEN

The α-synuclein (α-syn) amyloid fibrils are involved in various neurogenerative diseases. Solid-state NMR (ssNMR) has been showed as a powerful tool to study α-syn aggregates. Here, we report the 1H, 13C and 15N back-bone chemical shifts of a new α-syn polymorph obtained using proton-detected ssNMR spectroscopy under fast (95 kHz) magic-angle spinning conditions. The manual chemical shift assignments were cross-validated using FLYA algorithm. The secondary structural elements of α-syn fibrils were calculated using 13C chemical shift differences and TALOS software.

17.
Int J Mol Sci ; 25(13)2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-39000229

RESUMEN

Binding affinity is a fundamental parameter in drug design, describing the strength of the interaction between a molecule and its target protein. Accurately predicting binding affinity is crucial for the rapid development of novel therapeutics, the prioritization of promising candidates, and the optimization of their properties through rational design strategies. Binding affinity is determined by the mechanism of recognition between proteins and ligands. Various models, including the lock and key, induced fit, and conformational selection, have been proposed to explain this recognition process. However, current computational strategies to predict binding affinity, which are based on these models, have yet to produce satisfactory results. This article explores the connection between binding affinity and these protein-ligand interaction models, highlighting that they offer an incomplete picture of the mechanism governing binding affinity. Specifically, current models primarily center on the binding of the ligand and do not address its dissociation. In this context, the concept of ligand trapping is introduced, which models the mechanisms of dissociation. When combined with the current models, this concept can provide a unified theoretical framework that may allow for the accurate determination of the ligands' binding affinity.


Asunto(s)
Diseño de Fármacos , Unión Proteica , Proteínas , Ligandos , Proteínas/química , Proteínas/metabolismo , Conformación Proteica , Modelos Moleculares , Sitios de Unión , Humanos
18.
Heliyon ; 10(13): e33400, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39044974

RESUMEN

This work proves the local vertex anti-magic coloring of even regular circulant bipartite graphs C ( m ; L ) . Let G be either K r , r or K r , r - F , F is a 1-factor. Also, we discover the local vertex anti-magic coloring for union of bipartite graphs; join graphs G ∨ H , where H ∈ { O r , K r , C r , K r , s } ; and the upper bound of corona product G ⊙ O r . It was a problem Lau and Shiu (2023) [1] that: For any G 1 and G 2 , determine χ ℓ v a ( G 1 × G 2 ) . We give partial answer to this problem by proving the followings:1. χ ℓ v a ( C 2 m × C 2 n ) ;2. χ ℓ v a ( C 2 m + 1 × C 2 n + 2 ) ; and3. χ ℓ v a ( P 3 × H ) , where H ∈ { K r , K m , m } .

19.
J Struct Biol X ; 9: 100098, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-39010882

RESUMEN

Here we report the structure of Opa60 in lipid bilayers using proton-detected magic-angle spinning nuclear magnetic resonance (MAS NMR). Preparations including near-native oligosaccharide lipids reveal a consistent picture of a stable transmembrane beta barrel with a minor increase in the structured region as compared with the previously reported detergent structure. The large variable loops known to interact with host proteins could not be detected, confirming their dynamic nature even in a lipid bilayer environment. The structure provides a starting point for investigation of the functional role of Opa60 in gonococcal infection, which is understood to involve interaction with host proteins. At the same time, it demonstrates the recent advances in proton-detected methodology for membrane protein structure determination at atomic resolution by MAS NMR.

20.
J Magn Reson ; 365: 107724, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38991266

RESUMEN

Magic-angle spinning (MAS) solid-state nuclear magnetic resonance (SSNMR) spectroscopy is a powerful and versatile technique for probing structure and dynamics in large, insoluble biological systems at atomic resolution. With many recent advances in instrumentation and polarization methods, technology development in SSNMR remains an active area of research and presents opportunities to further improve data collection, processing, and analysis of samples with low sensitivity and complex tertiary and quaternary structures. SSNMR spectra are often collected as multidimensional data, requiring stable experimental conditions to minimize signal fluctuations (t1 noise). In this work, we examine the factors adversely affecting signal stability as well as strategies used to mitigate them, considering laboratory environmental requirements, configuration of amplifiers, and pulse sequence parameter selection. We show that Thermopad® temperature variable attenuators (TVAs) can partially compensate for the changes in amplifier output power as a function of temperature and thereby ameliorate one significant source of instability for some spectrometers and pulse sequences. We also consider the selection of tangent ramped cross polarization (CP) waveform shapes, to balance the requirements of sensitivity and instrumental stability. These findings collectively enable improved stability and overall performance for CP-based multidimensional spectra of microcrystalline, membrane, and fibrous proteins performed at multiple magnetic field strengths.


Asunto(s)
Espectroscopía de Resonancia Magnética , Espectroscopía de Resonancia Magnética/métodos , Resonancia Magnética Nuclear Biomolecular/métodos , Temperatura , Algoritmos
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