Novel fold of VirA, a type III secretion system effector protein from Shigella flexneri

Journal Article · Wed Jan 28 04:00:00 EST 2009 · Protein Sci.

DOI:https://doi.org/10.1110/ps.037978.108· OSTI ID:1007051

Davis, Jamaine; Wang, Jiawei; Tropea, Joseph E; Zhang, Di; Dauter, Zbigniew; Waugh, David S; Wlodawer, Alexander ^[1]

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1. SAIC

VirA, a secreted effector protein from Shigella sp., has been shown to be necessary for its virulence. It was also reported that VirA might be related to papain-like cysteine proteases and cleave {alpha}-tubulin, thus facilitating intracellular spreading. We have now determined the crystal structure of VirA at 3.0 {angstrom} resolution. The shape of the molecule resembles the letter 'V,' with the residues in the N-terminal third of the 45-kDa molecule (some of which are disordered) forming one clearly identifiable domain, and the remainder of the molecule completing the V-like structure. The fold of VirA is unique and does not resemble that of any known protein, including papain, although its N-terminal domain is topologically similar to cysteine protease inhibitors such as stefin B. Analysis of the sequence conservation between VirA and its Escherichia coli homologs EspG and EspG2 did not result in identification of any putative protease-like active site, leaving open a possibility that the biological function of VirA in Shigella virulence may not involve direct proteolytic activity.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1007051
• Journal Information: Protein Sci., Journal Name: Protein Sci. Journal Issue: (12) ; 12, 2008 Vol. 17
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
BIOLOGICAL FUNCTIONS
CRYSTAL STRUCTURE
CYSTEINE
ESCHERICHIA COLI
PAPAIN
PROTEINS
RESIDUES
RESOLUTION
SECRETION
SHAPE
SHIGELLA
VIRULENCE