In-Silico Structural and Functional Characterization of a V. cholerae O395 Hypothetical Protein Containing a PDZ1 and an Uncommon Protease Domain

Avirup Dutta,Keya Chaudhuri,Atul Katarkar,Eugene A Permyakov

doi:10.1371/journal.pone.0056725

Abstract

Vibrio cholerae, the causative agent of epidemic cholera, has been a constant source of concern for decades. It has constantly evolved itself in order to survive the changing environment. Acquisition of new genetic elements through genomic islands has played a major role in its evolutionary process. In this present study a hypothetical protein was identified which was present in one of the predicted genomic island regions of the large chromosome of V. cholerae O395 showing a strong homology with a conserved phage encoded protein. In-silico physicochemical analysis revealed that the hypothetical protein was a periplasmic protein. Homology modeling study indicated that the hypothetical protein was an unconventional and atypical serine protease belonging to HtrA protein family. The predicted 3D-model of the hypothetical protein revealed a catalytic centre serine utilizing a single catalytic residue for proteolysis. The predicted catalytic triad may help to deduce the active site for the recruitment of the substrate for proteolysis. The active site arrangements of this predicted serine protease homologue with atypical catalytic triad is expected to allow these proteases to work in different environments of the host.

Highlights

Vibrio cholerae, the most notable member of the Vibrionaceae family is the etiological agent of epidemic cholera, causing a severe and sometimes lethal diarrheal disease
Homology modeling study indicated that the hypothetical protein was an unconventional and atypical serine protease belonging to high temperature requirement A (HtrA) protein family
Identification of genomic islands in V. cholerae O395 Co-ordinates of statistically significant horizontally acquired genomic segments of V. cholerae O395 were determined by DesignIsland [27]

Summary

Introduction

The most notable member of the Vibrionaceae family is the etiological agent of epidemic cholera, causing a severe and sometimes lethal diarrheal disease. V. cholerae is classified into two serogroups: O1 and nonO1. The toxigenic strains of serogroups O1 and O139 have been found to cause cholera epidemics. There are two biotypes of V. cholerae O1, Classical and El Tor. There have been seven major pandemics since 1817. Isolates of the sixth pandemic were of O1 classical biotype [1]

Methods

Results

Conclusion