Investigating a Link Between CrvAB and Bacterial Pathogenesis Across Vibrio Species

Abstract

Bacteria have evolved distinct cell structures that confer advantages and dictate new functions. For example, the curved-rod shape of the pathogen, Vibrio cholerae, has been shown to promote its ability to cause the cholera disease. CrvA and CrvB are proteins that induce cell curvature within V. cholerae. These proteins are homologous, except for CrvB containing a unique CrvB-specific (CBS) domain. Each Crv protein contains a signal sequence, two coiled-coil domains, and a PEGA-like domain. Previous literature has confirmed that these Crv proteins are capable of inducing curvature in other non-curved bacterial species. However, previous work has not completely established a link between Crv protein-induced cell curvature and virulence in other bacterial species. In this paper, the established link between V. cholerae curvature and pathogenesis is investigated further by shifting focus towards the evolutionary conservation of CrvA and CrvB across clinically isolated pathogenic and non-pathogenic Vibrio species. In addition, we also observed the sequence distribution of crucial determinants of cholera pathogenicity among those species. The differences in CrvA and CrvB amino acid sequences across Vibrio species were quantified using alignment-based and alignment-free sequence analysis methods. We were able to identify patterns supporting the role of Crv proteins in pathogenesis. This paper provides evidence supporting the hypothesis of Crv proteins being evolutionarily consistent markers of bacterial pathogenesis.