RESUMEN

Aeromonas veronii, an opportunistic pathogen, is known to cause serious infections across various species. In our previous study, we discovered that A. veronii GL2 exhibited a virulence up to ten times greater than that of FO1. To ascertain the factors contributing to the disparity in virulence between the two strains, we conducted a comparative transcriptome analysis. This analysis reveals a significant upregulation (P < 0.05) of the ascR gene in GL2 compared with FO1. Additionally, six differentially expressed genes (DEGs) were identified within the "Bacterial secretion system" pathway (map03070), with ascR being an essential component of type III secretion system (T3SS). AscR, considered as SctR family export apparatus subunit within the T3SS, has ambiguous roles in the biological properties, gene expression profiles, virulence and colonization of A. veronii. Therefore, we constructed a mutant strain (ΔascR) by homologous recombination. Comparative analysis with the wide-type GL2 reveals no significant differences in terms of colony morphology, growth curve, hemolytic activity and protease activity. However, significant reductions (P < 0.01) were observed in the abilities of biofilm formation and swimming mobility. No remarkable difference was noted in the lengths of flagella. The LD50 value of ΔascR was to be 5.15 times higher than that of GL2. Interestingly, the mRNA expression of ascC, ascD, ascJ and ascI genes in the T3SS, and mshB, mshE, mshK and mshP genes in the MSHA type pili were significantly upregulated (P < 0.05) in ΔascR, potentially due to transcriptional compensation. Further analysis of enzymatic biomarkers revealed that ΔascR might not destruct the recognition of innate immune response in host remarkably, but the colonization levels of A.veronii were significantly suppressed (P < 0.01) in ΔascR group. In conclusion, the ascR gene may be a key determinant in regulating the virulence of A. veronii, and the destruction of the T3SS caused by ascR deficiency results in these notable changes.

Asunto(s)

Aeromonas veronii , Regulación Bacteriana de la Expresión Génica , Transcriptoma , Sistemas de Secreción Tipo III , Sistemas de Secreción Tipo III/genética , Sistemas de Secreción Tipo III/metabolismo , Aeromonas veronii/patogenicidad , Aeromonas veronii/genética , Virulencia/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Perfilación de la Expresión Génica , Biopelículas/crecimiento & desarrollo , Animales

RESUMEN

In bacterial flagellum biogenesis, secretion of the hook-filament junction proteins FlgK and FlgL and completion of the flagellum requires the FlgN chaperone. Similarly, the related FliT chaperone is necessary for the secretion of the filament cap protein FliD and binds the flagellar export gate protein FlhA and the flagellum ATPase FliI. FlgN and FliT require FliJ for effective substrate secretion. In Helicobacter pylori, neither FlgN, FliT, nor FliJ have been annotated. We demonstrate that the genome location of HP1120 is identical to that of flgN in other flagellated bacteria and that HP1120 is the homolog of Campylobacter jejuni FlgN. A modeled HP1120 structure contains three α-helices and resembles the FliT chaperone, sharing a similar substrate-binding pocket. Using pulldowns and thermophoresis, we show that both HP1120 and a HP1120Δ126-144 deletion mutant bind to FlgK with nanomolar affinity, but not to the filament cap protein FliD, confirming that HP1120 is FlgN. Based on size-exclusion chromatography and multi-angle light scattering, H. pylori FlgN binds to FlgK with 1:1 stoichiometry. Overall structural similarities between FlgN and FliT suggest that substrate recognition on FlgN primarily involves an antiparallel coiled-coil interface between the third helix of FlgN and the C-terminal helix of the substrate. A FlgNΔ126-144 N100A, Y103A, S111I triple mutant targeting this interface significantly impairs the binding of FlgK. Finally, we demonstrate that FlgNΔ126-144 , like FliT, binds with sub-micromolar affinity to the flagellum ATPase FliI or its N-terminal domain. Hence FlgN and FliT likely couple delivery of low-abundance export substrates to the flagellum ATPase FliI.

Asunto(s)

Adenosina Trifosfatasas , Helicobacter pylori , Adenosina Trifosfatasas/metabolismo , Proteínas Bacterianas/química , Chaperonas Moleculares/química , Flagelos/química , Flagelos/genética , Flagelos/metabolismo

RESUMEN

Many bacterial pathogens employ a protein complex, termed the type III secretion system (T3SS), to inject bacterial effectors into host cells. These effectors manipulate various cellular processes to promote bacterial growth and survival. The T3SS complex adopts a nano-syringe shape that is assembled across the bacterial membranes, with an extracellular needle extending toward the host cell membrane. The assembly of the T3SS is initiated by the association of three proteins, known as SctR, SctS, and SctT, which create an entry portal to the translocation channel within the bacterial inner membrane. Using the T3SS of enteropathogenic Escherichia coli, we investigated, by mutational and functional analyses, the role of two structural construction sites formed within the SctRST complex and revealed that they are mutation-resistant components that are likely to act as seals preventing leakage of ions and metabolites rather than as substrate gates. In addition, we identified two residues in the SctS protein, Pro23, and Lys54, that are critical for the proper activity of the T3SS. We propose that Pro23 is critical for the physical orientation of the SctS transmembrane domains that create the tip of the SctRST complex and for their positioning with regard to other T3SS substructures. Surprisingly, we found that SctS Lys54, which was previously suggested to mediate the SctS self-oligomerization, is critical for T3SS activity due to its essential role in SctS-SctT hetero-interactions.

Asunto(s)

Escherichia coli Enteropatógena/metabolismo , Proteínas de Escherichia coli/metabolismo , Sistemas de Secreción Tipo III/metabolismo , Secuencias de Aminoácidos , Escherichia coli Enteropatógena/química , Escherichia coli Enteropatógena/genética , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Unión Proteica , Dominios Proteicos , Sistemas de Secreción Tipo III/química , Sistemas de Secreción Tipo III/genética

RESUMEN

Diarrheal diseases remain a major public health concern worldwide. Many of the causative bacterial pathogens that cause these diseases have a specialized protein complex, the type III secretion system (T3SS), which delivers effector proteins directly into host cells. These effectors manipulate host cell processes for the benefit of the infecting bacteria. The T3SS structure resembles a syringe anchored within the bacterial membrane, projecting toward the host cell membrane. The entry port of the T3SS substrates, called the export apparatus, is formed by five integral membrane proteins. Among the export apparatus proteins, EscV is the largest, and as it forms a nonamer, it constitutes the largest portion of the export apparatus complex. While there are considerable data on the soluble cytoplasmic domain of EscV, our knowledge of its membrane-associated section and its transmembrane domains (TMDs) is still very limited. In this study, using an isolated genetic reporter system, we found that TMD5 and TMD6 of EscV mediate strong self-oligomerization. Substituting these TMDs within the full-length protein with a random hydrophobic sequence resulted in a complete loss of function of the T3SS, further suggesting that the EscV TMD5 and TMD6 sequences have a functional role in addition to their structural role as membrane anchors. As we observed only mild reduction in the ability of the TMD-exchanged variants to integrate into the full or intermediate T3SS complexes, we concluded that EscV TMD5 and TMD6 are not crucial for the global assembly or stability of the T3SS complex but are rather involved in promoting the necessary TMD-TMD interactions within the complex and the overall TMD orientation to allow channel opening for the entry of T3SS substrates.

RESUMEN

Type III protein secretion is widespread in Gram-negative pathogens. It comprises the injectisome with a surface-exposed needle and an inner membrane translocase. The translocase contains the SctRSTU export channel enveloped by the export gate subunit SctV that binds chaperone/exported clients and forms a putative ante-chamber. We probed the assembly, function, structure and dynamics of SctV from enteropathogenic E. coli (EPEC). In both EPEC and E. coli lab strains, SctV forms peripheral oligomeric clusters that are detergent-extracted as homo-nonamers. Membrane-embedded SctV9 is necessary and sufficient to act as a receptor for different chaperone/exported protein pairs with distinct C-domain binding sites that are essential for secretion. Negative staining electron microscopy revealed that peptidisc-reconstituted His-SctV9 forms a tripartite particle of ∼22 nm with a N-terminal domain connected by a short linker to a C-domain ring structure with a ∼5 nm-wide inner opening. The isolated C-domain ring was resolved with cryo-EM at 3.1 Å and structurally compared to other SctV homologues. Its four sub-domains undergo a three-stage "pinching" motion. Hydrogen-deuterium exchange mass spectrometry revealed this to involve dynamic and rigid hinges and a hyper-flexible sub-domain that flips out of the ring periphery and binds chaperones on and between adjacent protomers. These motions are coincident with local conformational changes at the pore surface and ring entry mouth that may also be modulated by the ATPase inner stalk. We propose that the intrinsic dynamics of the SctV protomer are modulated by chaperones and the ATPase and could affect allosterically the other subunits of the nonameric ring during secretion.

Asunto(s)

Adenosina Trifosfatasas/química , Escherichia coli Enteropatógena/ultraestructura , Proteínas de Escherichia coli/química , Flagelos/ultraestructura , Canales de Translocación SEC/química , Sistemas de Secreción Tipo III/ultraestructura , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Regulación Alostérica , Sitios de Unión , Clonación Molecular , Microscopía por Crioelectrón , Medición de Intercambio de Deuterio , Escherichia coli Enteropatógena/genética , Escherichia coli Enteropatógena/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Flagelos/genética , Flagelos/metabolismo , Expresión Génica , Regulación Bacteriana de la Expresión Génica , Vectores Genéticos/química , Vectores Genéticos/metabolismo , Cinética , Espectrometría de Masas , Modelos Moleculares , Chaperonas Moleculares/química , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Subunidades de Proteína/química , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Canales de Translocación SEC/genética , Canales de Translocación SEC/metabolismo , Especificidad por Sustrato , Sistemas de Secreción Tipo III/genética , Sistemas de Secreción Tipo III/metabolismo

RESUMEN

Virulence-associated type III secretion systems (T3SS) are utilized by Gram negative bacterial pathogens for injection of effector proteins into eukaryotic host cells. The transmembrane export apparatus at the core of T3SS is composed of a unique helical complex of the hydrophobic proteins SctR, SctS, SctT, and SctU. These components comprise a number of highly conserved charged residues within their hydrophobic domains. The structure of the closed state of the core complex SctR5S4T1 revealed that several of these residues form inter- and intramolecular salt bridges, some of which have to be broken for pore opening. Mutagenesis of individual residues was shown to compromise assembly or secretion of both, the virulence-associated and the related flagellar T3SS. However, the exact role of these conserved charged residues in the assembly and function of T3SS remains elusive. Here we performed an in-depth mutagenesis analysis of these residues in the T3SS of Salmonella Typhimurium, coupled to blue native PAGE, in vivo photocrosslinking and luciferase-based secretion assays. Our data show that these conserved salt bridges are not critical for assembly of the respective protein but rather facilitate the incorporation of the following subunit into the assembling complex. Our data also indicate that these conserved charged residues are critical for type III-dependent secretion and reveal a functional link between SctSE44 and SctTR204 and the cytoplasmic domain of SctU in gating the T3SS injectisome. Overall, our analysis provides an unprecedented insight into the delicate requirements for the assembly and function of the machinery at the core of T3SS.

Asunto(s)

Salmonella enterica/metabolismo , Sistemas de Secreción Tipo III/química , Sistemas de Secreción Tipo III/metabolismo , Modelos Moleculares , Complejos Multiproteicos/metabolismo , Mutación , Conformación Proteica , Dominios Proteicos , Salmonella enterica/genética , Salmonella enterica/patogenicidad , Sistemas de Secreción Tipo III/genética , Virulencia

RESUMEN

The bacterial flagellar motor is a supramolecular protein machine that drives rotation of the flagellum for motility, which is essential for bacterial survival in different environments and a key determinant of pathogenicity. The detailed structure of the flagellar motor remains unknown. Here we present an atomic-resolution cryoelectron microscopy (cryo-EM) structure of the bacterial flagellar motor complexed with the hook, consisting of 175 subunits with a molecular mass of approximately 6.3 MDa. The structure reveals that 10 peptides protruding from the MS ring with the FlgB and FliE subunits mediate torque transmission from the MS ring to the rod and overcome the symmetry mismatch between the rotational and helical structures in the motor. The LP ring contacts the distal rod and applies electrostatic forces to support its rotation and torque transmission to the hook. This work provides detailed molecular insights into the structure, assembly, and torque transmission mechanisms of the flagellar motor.

Asunto(s)

Flagelos/fisiología , Flagelos/ultraestructura , Salmonella typhimurium/fisiología , Microscopía por Crioelectrón , Conformación Proteica , Torque

RESUMEN

One of the central systems responsible for bacterial motility is the flagellum. The bacterial flagellum is a macromolecular protein complex that is more than five times the cell length. Flagella-driven motility is coordinated via a chemosensory signal transduction pathway, and so bacterial cells sense changes in the environment and migrate towards more desirable locations. The flagellum of Salmonella enterica serovar Typhimurium is composed of a bi-directional rotary motor, a universal joint and a helical propeller. The flagellar motor, which structurally resembles an artificial motor, is embedded within the cell envelop and spins at several hundred revolutions per second. In contrast to an artificial motor, the energy utilized for high-speed flagellar motor rotation is the inward-directed proton flow through a transmembrane proton channel of the stator unit of the flagellar motor. The flagellar motor realizes efficient chemotaxis while performing high-speed movement by an ingenious directional switching mechanism of the motor rotation. To build the universal joint and helical propeller structures outside the cell body, the flagellar motor contains its own protein transporter called a type III protein export apparatus. In this chapter we summarize the structure and assembly of the Salmonella flagellar motor complex.

Asunto(s)

Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Flagelos/química , Flagelos/metabolismo , Proteínas Motoras Moleculares/química , Proteínas Motoras Moleculares/metabolismo , Salmonella typhimurium/química , Salmonella typhimurium/metabolismo

RESUMEN

The bacterial injectisome and flagella both rely on type III secretion systems for their assembly. The syringe-like injectisome creates a continuous channel between the bacterium and the host cell, through which signal-modulating effector proteins are secreted. The inner membrane pore protein SctV controls the hierarchy of substrate selection and may also be involved in energizing secretion. We present the 4.7 Å cryo-EM structure of the SctV cytosolic domain (SctVC) from the enteropathogenic Escherichia coli injectisome. SctVC forms a nonameric ring with primarily electrostatic interactions between its subunits. Molecular dynamics simulations show that monomeric SctVC maintains a closed conformation, in contrast with previous studies on flagellar homologue FlhA. Comparison with substrate-bound homologues suggest that a conformational change would be required to accommodate binding partners.

Asunto(s)

Citosol/metabolismo , Escherichia coli Enteropatógena/metabolismo , Proteínas de Escherichia coli/metabolismo , Flagelos/metabolismo , Sistemas de Secreción Tipo III/metabolismo , Microscopía por Crioelectrón/métodos , Proteínas de la Membrana/metabolismo , Subunidades de Proteína/metabolismo , Transporte de Proteínas/fisiología

RESUMEN

The bacterial flagellum is a filamentous organelle extending from the cell surface. The axial structure of the flagellum consists of the rod, hook, junction, filament, and cap. The axial structure is formed by axial component proteins exported via a specific protein export apparatus in a well-regulated manner. Although previous studies have revealed the outline of the flagellar construction process, the mechanism of axial structure formation, including axial protein export, is still obscure due to difficulties in direct observation of protein export and assembly in vivo. We recently developed an in vitro flagellar protein transport assay system using inverted membrane vesicles (IMVs) and succeeded in reproducing the early stage of flagellar assembly. However, the late stage of the flagellar formation process remained to be examined in the IMVs. In this study, we showed that the filament-type proteins are transported into the IMVs to produce the filament on the hook inside the IMVs. Furthermore, we provide direct evidence that coordinated flagellar protein export and assembly can occur at the post-translational level. These results indicate that the ordered construction of the entire flagellar structure can be regulated by only the interactions between the protein export apparatus, the export substrate proteins, and their cognate chaperones.

Asunto(s)

Flagelos/metabolismo , Salmonella typhimurium/metabolismo , Proteínas Bacterianas/metabolismo , Humanos , Proteínas de la Membrana/metabolismo , Transporte de Proteínas , Infecciones por Salmonella/microbiología , Sistemas de Secreción Tipo III/metabolismo

RESUMEN

The bacterial flagellum is a supramolecular motility machine consisting of the basal body, the hook, and the filament. For construction of the flagellum beyond the cellular membranes, a type III protein export apparatus uses ATP and proton-motive force (PMF) across the cytoplasmic membrane as the energy sources to transport flagellar component proteins from the cytoplasm to the distal end of the growing flagellar structure. The protein export apparatus consists of a PMF-driven transmembrane export gate complex and a cytoplasmic ATPase complex. In addition, the basal body C ring acts as a sorting platform for the cytoplasmic ATPase complex that efficiently brings export substrates and type III export chaperone-substrate complexes from the cytoplasm to the export gate complex. In this book chapter, we will summarize our current understanding of molecular organization and assembly of the flagellar type III protein export apparatus.

Asunto(s)

Sistemas de Secreción Tipo III/biosíntesis , Sistemas de Secreción Tipo III/química , Proteínas Bacterianas , Flagelos , Transporte de Proteínas , ATPasas de Translocación de Protón/química , ATPasas de Translocación de Protón/metabolismo , Sistemas de Secreción Tipo III/metabolismo

RESUMEN

Bacteria use a type III protein export apparatus for construction of the flagellum, which consists of the basal body, the hook, and the filament. FlhA forms a homo-nonamer through its C-terminal cytoplasmic domains (FlhAC) and ensures the strict order of flagellar assembly. FlhAC goes through dynamic domain motions during protein export, but it remains unknown how it occurs. Here, we report that the FlhA(G368C) mutation biases FlhAC toward a closed form, thereby reducing the binding affinity of FlhAC for flagellar export chaperones in complex with their cognate filament-type substrates. The G368C mutations also restrict the conformational flexibility of a linker region of FlhA (FlhAL), suppressing FlhAC ring formation. We propose that interactions of FlhAL with its neighboring subunit converts FlhAC in the ring from a closed conformation to an open one, allowing the chaperon/substrate complexes to bind to the FlhAC ring to form the filament at the hook tip.

Asunto(s)

Proteínas Bacterianas/metabolismo , Flagelos/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Cristalografía por Rayos X , Citoplasma/genética , Citoplasma/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , Modelos Moleculares , Chaperonas Moleculares/química , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Mutación , Unión Proteica , Conformación Proteica , Transporte de Proteínas/genética

RESUMEN

Microbiota and intestinal epithelium restrict pathogen growth by rapid nutrient consumption. We investigated how pathogens circumvent this obstacle to colonize the host. Utilizing enteropathogenic E. coli (EPEC), we show that host-attached bacteria obtain nutrients from infected host cell in a process we termed host nutrient extraction (HNE). We identified an inner-membrane protein complex, henceforth termed CORE, as necessary and sufficient for HNE. The CORE is a key component of the EPEC injectisome, however, here we show that it supports the formation of an alternative structure, composed of membranous nanotubes, protruding from the EPEC surface to directly contact the host. The injectisome and flagellum are evolutionarily related, both containing conserved COREs. Remarkably, CORE complexes of diverse ancestries, including distant flagellar COREs, could rescue HNE capacity of EPEC lacking its native CORE. Our results support the notion that HNE is a widespread virulence strategy, enabling pathogens to thrive in competitive niches.

Asunto(s)

Escherichia coli Enteropatógena/patogenicidad , Proteínas de Escherichia coli/metabolismo , Nutrientes/metabolismo , Aminoácidos/metabolismo , Adhesión Bacteriana/fisiología , Escherichia coli Enteropatógena/crecimiento & desarrollo , Escherichia coli Enteropatógena/metabolismo , Fluoresceínas/metabolismo , Células HeLa , Humanos , Proteínas de la Membrana/metabolismo , Microscopía Electrónica de Rastreo , Microscopía Fluorescente

RESUMEN

We have previously described the existence of membranous nanotubes, bridging adjacent bacteria, facilitating intercellular trafficking of nutrients, cytoplasmic proteins, and even plasmids, yet components enabling their biogenesis remain elusive. Here we reveal the identity of a molecular apparatus providing a platform for nanotube biogenesis. Using Bacillus subtilis (Bs), we demonstrate that conserved components of the flagellar export apparatus (FliO, FliP, FliQ, FliR, FlhB, and FlhA), designated CORE, dually serve for flagellum and nanotube assembly. Mutants lacking CORE genes, but not other flagellar components, are deficient in both nanotube production and the associated intercellular molecular trafficking. In accord, CORE components are located at sites of nanotube emergence. Deleting COREs of distinct species established that CORE-mediated nanotube formation is widespread. Furthermore, exogenous COREs from diverse species could restore nanotube generation and functionality in Bs lacking endogenous CORE. Our results demonstrate that the CORE-derived nanotube is a ubiquitous organelle that facilitates intercellular molecular trade across the bacterial kingdom.

Asunto(s)

Proteínas Bacterianas/metabolismo , Nanotubos/química

RESUMEN

Many Gram-negative bacterial pathogens utilize a specialized protein delivery system, called the type III secretion system (T3SS), to translocate effector proteins into the host cells. The translocated effectors are crucial for bacterial infection and survival. The base of the T3SS transverses both bacterial membranes and contains an export apparatus that comprises five membrane proteins. Here, we study the export apparatus of enteropathogenic Escherichia coli (EPEC) and characterize its central component, called the EscR protein. We found that the third transmembrane domain (TMD) of EscR mediates strong self-oligomerization in an isolated genetic reporter system. Replacing this TMD sequence with an alternative hydrophobic sequence within the full-length protein resulted in a complete loss of function of the T3SS, further suggesting that the EscR TMD3 sequence has another functional role in addition to its role as a membrane anchor. Moreover, we found that an aspartic acid residue, located at the core of EscR TMD3, is important for the oligomerization propensity of TMD3 and that a point mutation of this residue within the full-length protein abolishes the T3SS activity and the ability of the bacteria to translocate effectors into host cells.IMPORTANCE Many Gram-negative bacterial pathogens that cause life-threatening diseases employ a type III secretion system (T3SS) for their virulence. The T3SS comprises several proteins that assemble into a syringe-like structure dedicated to the injection of bacterial virulence factors into the host cells. Although many T3SS proteins are transmembrane proteins, our knowledge of these proteins is limited mostly to their soluble domains. In this study, we found that the third transmembrane domain (TMD) of EscR, a central protein of the T3SS in enteropathogenic E. coli, contributes to protein self-oligomerization. Moreover, we demonstrated that a single aspartic acid residue, located at the core of this TMD, is critical for the activity of the full-length protein and the function of the entire T3SS, possibly due to its involvement in mediating TMD-TMD interactions. Our findings should encourage the mapping of the entire interactome of the T3SS components, including interactions mediated through their TMDs.

Asunto(s)

Escherichia coli Enteropatógena/metabolismo , Sistemas de Secreción Tipo III/metabolismo , Escherichia coli Enteropatógena/genética , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Mutación Missense , Dominios Proteicos , Multimerización de Proteína , Sistemas de Secreción Tipo III/genética

RESUMEN

The bacterial flagellar proteins are transported via a specific export apparatus to the distal end of the growing structure for their self-assembly. FliP is an essential membrane component of the export apparatus. FliP has an N-terminal signal peptide and is predicted to have four transmembrane (TM) helices and a periplasmic domain (FliPP) between TM-2 and TM-3. In this study, FliPP from Thermotoga maritima (TmFliPP) and its selenomethionine derivative (SeMet-TmFliPP) were purified and crystallized. TmFliPP formed a homotetramer in solution. Crystals of TmFliPP and SeMet-TmFliPP were obtained by the hanging-drop vapour-diffusion technique with 2-methyl-2,4-pentanediol as a precipitant. These two crystals grew in the hexagonal space group P6222 or P6422, with unit-cell parameters a = b = 114.9, c = 193.8 Å. X-ray diffraction data were collected from crystals of TmFliPP and SeMet-TmFliPP to 2.4 and 2.8 Šresolution, respectively.

Asunto(s)

Proteínas Bacterianas/química , Flagelos/química , Periplasma/química , Secuencia de Bases , Cristalización , Cartilla de ADN , Reacción en Cadena de la Polimerasa , Transporte de Proteínas