scholarly journals Crystal structure of the C-terminal domain of the Salmonella type III secretion system export apparatus protein InvA

2010 ◽  
Vol 19 (5) ◽  
pp. 1091-1096 ◽  
Author(s):  
Liam J. Worrall ◽  
Marija Vuckovic ◽  
Natalie C. J. Strynadka
2014 ◽  
Vol 70 (10) ◽  
pp. 1431-1433 ◽  
Author(s):  
Gitte Meriläinen ◽  
Rik K. Wierenga

The inner membrane ring of the bacterial type III secretion system (TTSS) is composed of two proteins. InChlamydia trachomatisthis ring is formed by CdsD (gene nameCT_664) and CdsJ (gene nameCTA_0609). CdsD consists of 829 amino acids. The last 400 amino acids at its C-terminal end relate it to the type III secretion system YscD/HrpQ protein family. The C-terminal domain, consisting of amino acids 558–771, ofC. trachomatisCdsD was overexpressed inEscherichia coliand purified using immobilized metal-affinity chromatography (IMAC) and size-exclusion chromatography. The protein was crystallized using the vapour-diffusion method. A data set was collected to 2.26 Å resolution. The crystals have the symmetry of space groupC2, with unit-cell parametersa= 106.60,b= 23.91,c= 118.65 Å, β = 104.95°. According to the data analysis there is expected to be one molecule in the asymmetric unit, with a Matthews coefficient of 3.0 Å3 Da−1.


2014 ◽  
Vol 464 (1) ◽  
pp. 135-144 ◽  
Author(s):  
Samira Zouhir ◽  
Joaquín Bernal-Bayard ◽  
Mar Cordero-Alba ◽  
Elena Cardenal-Muñoz ◽  
Beatriz Guimaraes ◽  
...  

We report the crystal structure of the Salmonella effector SlrP in complex with its human protein target thioredoxin Trx1. SlrP is a E3 ubiquitin ligase from the NEL family and we present evidence for the site of ubiquitination on Trx1.


2015 ◽  
Vol 71 (10) ◽  
pp. 1300-1308 ◽  
Author(s):  
Brianne J. Burkinshaw ◽  
Sergio A. Souza ◽  
Natalie C. J. Strynadka

During infection, enteropathogenicEscherichia coliassembles a complex multi-protein type III secretion system that traverses the bacterial membranes and targets the host cell membrane to directly deliver virulence or effector proteins to the host cytoplasm. As this secretion system is composed of more than 20 proteins, many of which form oligomeric associations, its assembly must be tightly regulated. A protein called the gatekeeper, or SepL, ensures that the secretion of the translocon component, which inserts into the host membrane, occurs before the secretion of effectors. The crystal structure of the gatekeeper SepL was determined and compared with the structures of SepL homologues from other bacterial pathogens in order to identify SepL residues that may be critical for its role in type III secretion-system assembly.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Peng Li ◽  
Giomar Rivera-Cancel ◽  
Lisa N Kinch ◽  
Dor Salomon ◽  
Diana R Tomchick ◽  
...  

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.


PLoS ONE ◽  
2011 ◽  
Vol 6 (4) ◽  
pp. e19208 ◽  
Author(s):  
Chiradip Chatterjee ◽  
Sundramurthy Kumar ◽  
Smarajit Chakraborty ◽  
Yih Wan Tan ◽  
Ka Yin Leung ◽  
...  

2009 ◽  
Vol 191 (12) ◽  
pp. 3811-3821 ◽  
Author(s):  
Evan D. Brutinel ◽  
Christopher A. Vakulskas ◽  
Timothy L. Yahr

ABSTRACT The opportunistic pathogen Pseudomonas aeruginosa utilizes a type III secretion system (T3SS) to evade phagocytosis and damage eukaryotic cells. Transcription of the T3SS regulon is controlled by ExsA, a member of the AraC/XylS family of transcriptional regulators. These family members generally consist of an ∼100-amino acid carboxy-terminal domain (CTD) with two helix-turn-helix DNA binding motifs and an ∼200-amino acid amino-terminal domain (NTD) with known functions including oligomerization and ligand binding. In the present study, we show that the CTD of ExsA binds to ExsA-dependent promoters in vitro and activates transcription from ExsA-dependent promoters both in vitro and in vivo. Despite possessing these activities, the CTD lacks the cooperative binding properties observed for full-length ExsA at the P exsC promoter. In addition, the CTD is unaffected by the negative regulatory activity of ExsD, an inhibitor of ExsA activity. Binding studies confirm that ExsD interacts directly with the NTD of ExsA. Our data are consistent with a model in which a single ExsA molecule first binds to a high-affinity site on the P exsC promoter. Protein-protein interactions mediated by the NTD then recruit an additional ExsA molecule to a second site on the promoter to form a complex capable of stimulating wild-type levels of transcription. These findings provide important insight into the mechanisms of transcriptional activation by ExsA and inhibition of ExsA activity by ExsD.


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