Expression of the envelope antigen F1 of Yersinia pestis is mediated by the product of caf1M gene having homology with the chaperone protein PapD of Escherichia coli

Abstract

The effective synthesis of the envelope antigen Fl of Y. pestis in E. coli HBlOl is mediated by the expression of the cuflM gene. This gene was sequenced, and the protein encoded was found to have a significant homology with the chaperone protein PapD of uropathopnic E. coli. The data presented allow one to suppose CaflM and PapD proteins perform similar functions in the biogenesis of the Y. pestis capsule and E. coli P-pili, respectively.

Specific high affinity binding of human interleukin 1β by Caf1A usher protein of Yersinia pestis

“…Plasmid p l2R [8] has been described. For overexpression ofcaflM, the caflMgene was isolated on a 0.8 kb BspHI-SmaI DNA fragment from pl2R and ligated into NcoI-HpaI digested pTrc99a vector (Pharmacia) to give pTCA1.…”

“…(ii) Identification of CaflM. A synthetic peptide corresponding to residues 135-150 of CaflM [8] i.e. the additional loop in comparison with the known periplasmic molecular chaperones [8,11] was synthesized by the semi-automatic continuous-flow solid phase method [20].…”

“…coli HB101 cells transformed by a recombinant plasmid (pl2R), which carries the major fragment of the fl operon of Y pestis, produce a functional periplasmic chaperone (Cafl M), outer membrane usher protein (CaflA) and capsular polypeptide (Cafl) as indicated by the expression and assembly of the E pestis capsular polypeptide at the surface of E. coli [8]. Levels of capsular polypeptide are somewhat lower in this strain compared to levels of capsule in E. coli pFS2 due to the truncation of the gene for the transcriptional regulator, caflR in pl2R (Karlyshev, unpublished observations).…”

“…lb, lane 2). In comparison with plasmid pUC 19, plasmid p 12R contains only four additional genes -those responsible for expression of the preCafl (17.6 kDa), preCaflM (28.8 kDa), preCaflA (93.6 kDa) and CaflR (36 kDa) proteins [3,[8][9][10]. Thus the outer membrane usher protein, CaflA (mature polypeptide, putative M, --90.4) appeared to represent an obvious candidate as receptor for specific binding of hIL-lfl to E. coli cells expressing the fl operon.…”

“…It consists of four genes responsible for the synthesis and surface assembly of F1 capsule cafl, caflM, caflA and caflR encoding, respectively, the capsular protein Cafl [3], CaflM (capsule antigen F1 mediator) [8], CaflA (capsule antigen F1 assembly) [9] and a DNA-binding transcriptional regulator Cafl R [10]. Thefl operon is one of the simplest members of a widespread family of surface assembly related operons the prototype model of which is the pap operon involved in Pap pili assembly in uropathogenic E. coli [11][12][13][14].…”