Putative cell wall-binding proteins of Streptococcus suis serotype 2 isolate 98HAH33 identified by bioinformatic genome analysis / 中国人兽共患病学报

ABSTRACT

To identify the cell wall-binding proteins of Streptococcus suis serotype 2(SS2), according to their structure feature, the substrates of sortase and I type secreted proteins with LysM domain, WxL domain, choline-binding domain,GW domain or S layer homologous domain in the recently published genome of SS2 strain 98HAH33 were firstly identified and then the putative functions were attributed to individual proteins by reference to the identification of conserved domains of InterPro and BlastP servers. Homologous proteins were identified by unfiltered BlastP homology searches (including conserved domain detection). Among the 23 putative proteins with a C-terminal LPXTG recognition signal for covalent attachment to peptidoglycan by sortase, 9 with I signal peptide were identified as sortase substrates. Among 9 substrates , YP_001201232, YP_001201531 and YP_001201656 had been experimentally verified to anchor to bacterial cell wall , and YP_001201232 known as the opacity factor of S. suis (OFS) was proved to be the virulence factors. According to function analysis, YP_001201484, YP_001201544, YP_001199825, YP_001197640, YP_001197840 and YP_001199755 appeared to be involved in SS2 pathogenesis. and YP_001200959, YP_001201233 and two proteins with LysM domain( YP_001199784 and YP_001201729) were the hypothetical proteins. These data suggest the majority of putative sortase substrates may implicate in the virulence of SS2 and could serve as a basis for targeted experimental studies into the function of these proteins.