scholarly journals Conformational Changes in IpaD fromShigella flexneriupon Binding Bile Salts Provide Insight into the Second Step of Type III Secretion

Biochemistry ◽  
2011 ◽  
Vol 50 (2) ◽  
pp. 172-180 ◽  
Author(s):  
Nicholas E. Dickenson ◽  
Lingling Zhang ◽  
Chelsea R. Epler ◽  
Philip R. Adam ◽  
Wendy L. Picking ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Type Iii Secretion ◽  
Bile Salts ◽  
Second Step ◽  
Type Iii ◽  
Insight Into

scholarly journals Studying Conformational Changes of the Yersinia Type-III-Secretion Effector YopO in Solution by Integrative Structural Biology

Structure ◽  
2019 ◽  
Vol 27 (9) ◽  
pp. 1416-1426.e3 ◽  
Author(s):  
Martin F. Peter ◽  
Anne T. Tuukkanen ◽  
Caspar A. Heubach ◽  
Alexander Selsam ◽  
Fraser G. Duthie ◽  
...  
Keyword(s):  
Structural Biology ◽  
Conformational Changes ◽  
Type Iii Secretion ◽  
Type Iii ◽  
Integrative Structural Biology ◽  
Type Iii Secretion Effector

scholarly journals VopF, a type III effector protein from a non-O1, non-O139 Vibrio cholerae strain, demonstrates toxicity in a Saccharomyces cerevisiae model

2010 ◽  
Vol 59 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Ranjana Tripathi ◽  
Santa Singh Naorem ◽  
Chetna Dureja ◽  
Swati Haldar ◽  
Alok K. Mondal ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Type Iii Secretion ◽  
Ectopic Expression ◽  
Contributory Factor ◽  
Cholerae Strain ◽  
Effector Protein ◽  
Intestinal Colonization ◽  
Type Iii Effector ◽  
Type Iii ◽  
Insight Into

VopF, a type III effector protein, has been identified as a contributory factor to the intestinal colonization of type III secretion system-positive, non-O1, non-O139 Vibrio cholerae strains. To gain more insight into the function of VopF, a yeast model was developed. Using this model, it was found that ectopic expression of VopF conferred toxicity in yeast.

scholarly journals Regulation of Pseudomonas aeruginosa virulence by the ExsACDE Signaling Cascade

2014 ◽  
Vol 70 (a1) ◽  
pp. C1393-C1393
Author(s):  
Robert Bernhards ◽  
Xiao Yi ◽  
Manisha Shrestha ◽  
Florian Schubot
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Crystal Structures ◽  
Conformational Changes ◽  
Type Iii Secretion ◽  
Negative Regulator ◽  
Signaling Cascade ◽  
Regulation Of Transcription ◽  
Regulatory Domain ◽  
Type Iii ◽  
Dimerization Interface

Pseudomonas aeruginosa requires its type III secretion system (T3SS) to facilitate acute infections. T3SS-related gene expression is controlled by the AraC-type transcriptional activator ExsA. A signaling cascade involving ExsA and three additional proteins -ExsC, ExsD, and ExsE directly ties the up-regulation of transcription to the activation of the type III secretion apparatus. In order to characterize the molecular interactions underlying the signaling process the crystal structures of the unique T3SS chaperone ExsC in complex with its cognate effector ExsE, the structure of the negative regulator ExsD and that of the regulatory domain of ExsA have been determined. The ExsC-ExsE structure revealed two Arg-X-Val-X-Arg motifs in ExsE that form identical interactions along opposite sides of the ExsC dimer. The structure of ExsD not only provided insights into the interactions of how ExsD is sequestered by ExsC but also revealed surprising similarities between ExsD and DNA binding proteins. Based on these findings, a new model for the ExsC-ExsD complex is proposed to explain its distinctive 2:2 stoichiometry and why ExsC displays a weaker affinity for ExsD than for ExsE. Lastly, we have determined the structure of ExsA regulatory domain revealing the protein's dimerization interface. The position of the interface appears to postulate interesting conformational changes upon binding of ExsA to DNA. The crystal structures of ExsD and the ExsA domain also serve as road maps for determining the interface for the critical interactions between these two proteins at the bottom of this unique signaling cascade.

scholarly journals Analysis of Putative Chlamydia trachomatis Chaperones Scc2 and Scc3 and Their Use in the Identification of Type III Secretion Substrates

2005 ◽  
Vol 187 (18) ◽  
pp. 6466-6478 ◽  
Author(s):  
Kenneth A. Fields ◽  
Elizabeth R. Fischer ◽  
David J. Mead ◽  
Ted Hackstadt
Keyword(s):  
Chlamydia Trachomatis ◽  
Type Iii Secretion ◽  
Translocator Protein ◽  
Type Iii ◽  
Functional Studies ◽  
Infected Cells ◽  
Obligate Intracellular Pathogen ◽  
Insight Into

ABSTRACT The obligate intracellular pathogen Chlamydia trachomatis expresses a type III secretion system (T3SS) which has the potential to contribute significantly to pathogenesis. Based on a demonstrated role of type III secretion (T3S)-specific chaperones in the secretion of antihost proteins by gram-negative pathogens, we initiated a study of selected putative Chlamydia T3S chaperones in an effort to gain mechanistic insight into the Chlamydia T3SS and to potentially identify Chlamydia-specific secreted products. C. trachomatis Scc2 and Scc3 are homologous to SycD of Yersinia spp. Functional studies of the heterologous Yersinia T3SS indicated that although neither Scc2 nor Scc3 was able to fully complement a sycD null mutant, both have SycD-like characteristics. Both were able to associate with the translocator protein YopD, and Scc3 expression restored limited secretion of YopD in in vitro studies of T3S. CopB (CT578) and CopB2 (CT861) are encoded adjacent to scc2 and scc3, respectively, and have structural similarities with the YopB family of T3S translocators. Either Scc2 or Scc3 coprecipitates with CopB from C. trachomatis extracts. Expression of CopB or CopB2 in Yersinia resulted in their type III-dependent secretion, and localization studies with C. trachomatis-infected cells indicated that both were secreted by Chlamydia.

scholarly journals Insight into the flagella type III export revealed by the complex structure of the type III ATPase and its regulator

2016 ◽  
Vol 113 (13) ◽  
pp. 3633-3638 ◽  
Author(s):  
Katsumi Imada ◽  
Tohru Minamino ◽  
Yumiko Uchida ◽  
Miki Kinoshita ◽  
Keiichi Namba
Keyword(s):  
Complex Formation ◽  
Cell Membrane ◽  
Type Iii Secretion ◽  
Complex Structure ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Common Origin ◽  
Peripheral Stalk ◽  
Type Iii ◽  
Insight Into

FliI and FliJ form the FliI6FliJ ATPase complex of the bacterial flagellar export apparatus, a member of the type III secretion system. The FliI6FliJ complex is structurally similar to the α3β3γ complex of F1-ATPase. The FliH homodimer binds to FliI to connect the ATPase complex to the flagellar base, but the details are unknown. Here we report the structure of the homodimer of a C-terminal fragment of FliH (FliHC2) in complex with FliI. FliHC2shows an unusually asymmetric homodimeric structure that markedly resembles the peripheral stalk of the A/V-type ATPases. The FliHC2–FliI hexamer model reveals that the C-terminal domains of the FliI ATPase face the cell membrane in a way similar to the F/A/V-type ATPases. We discuss the mechanism of flagellar ATPase complex formation and a common origin shared by the type III secretion system and the F/A/V-type ATPases.

scholarly journals The Herbal Compound Thymol Targets Multiple Salmonella Typhimurium Virulence Factors for Lon Protease Degradation

2021 ◽  
Vol 12 ◽  
Author(s):  
Yong Zhang ◽  
Yan Liu ◽  
Jingjing Luo ◽  
Jing Jie ◽  
Xuming Deng ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Conformational Changes ◽  
Type Iii Secretion ◽  
Mammalian Cells ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Cells ◽  
Lon Protease ◽  
Type Iii ◽  
Pathogenic Factors

Many important bacterial pathogens are using the type III secretion system to deliver effectors into host cells. Salmonella Typhimurium (S. Typhimurium) is a pathogenic Gram-negative bacterium with the type III secretion system as its major virulence factor. Our previous studies demonstrated that thymol, a monoterpene phenol derivative of cymene, inhibited S. Typhimurium invasion into mammalian cells and protected mice from infection. However, the antibacterial mechanism of thymol is not clear. In this study, we revealed that thymol interferes with the abundance of about 100 bacterial proteins through proteomic analysis. Among the 42 proteins whose abundance was reduced, 11 were important virulence factors associated with T3SS-1. Further analyses with SipA revealed that thymol directly interacts with this protein to induce conformational changes, which makes it susceptible to the Lon protease. In agreement with this observation, thymol effectively blocks cell invasion by S. Typhimurium. Thus, thymol represents a class of anti-virulence compounds that function by targeting pathogenic factors for degradation.

scholarly journals Bile salt receptor complex activates a pathogenic type III secretion system

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Peng Li ◽  
Giomar Rivera-Cancel ◽  
Lisa N Kinch ◽  
Dor Salomon ◽  
Diana R Tomchick ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Bile Salt ◽  
Type Iii Secretion ◽  
Bile Salts ◽  
Mutational Analysis ◽  
Type Iii Secretion System ◽  
Antimicrobial Activities ◽  
Secretion System ◽  
Type Iii ◽  
Signaling Receptors

Bile is an important component of the human gastrointestinal tract with an essential role in food absorption and antimicrobial activities. Enteric bacterial pathogens have developed strategies to sense bile as an environmental cue to regulate virulence genes during infection. We discovered that Vibrio parahaemolyticus VtrC, along with VtrA and VtrB, are required for activating the virulence type III secretion system 2 in response to bile salts. The VtrA/VtrC complex activates VtrB in the presence of bile salts. The crystal structure of the periplasmic domains of the VtrA/VtrC heterodimer reveals a β-barrel with a hydrophobic inner chamber. A co-crystal structure of VtrA/VtrC with bile salt, along with biophysical and mutational analysis, demonstrates that the hydrophobic chamber binds bile salts and activates the virulence network. As part of a family of conserved signaling receptors, VtrA/VtrC provides structural and functional insights into the evolutionarily conserved mechanism used by bacteria to sense their environment.

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