Conserved immunoglobulin-like features in a family of periplasmic pilus chaperones in bacteria.

Abstract

Detailed structural analyses revealed a family of periplasmic chaperones in Gram‐negative prokaryotes which are structurally and possibly evolutionarily related to the immunoglobulin superfamily and assist in the assembly of adhesive pili. The members of this family have similar structures consistent with the overall topology of an immunoglobulin fold. Seven pilus chaperone sequences from Escherichia coli, Haemophilus influenzae and Klebsiella pneumoniae were aligned and their consensus sequence was superimposed onto the known three‐dimensional structure of PapD, a representative member of the family. The molecular details of the conserved and variable structural motifs in this family of periplasmic chaperones give important insight into their structure, function, mechanism of action and evolutionary relationship with the immunoglobulin superfamily.

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

“…2b that purified CaflA effectively inhibited [125I]IL-lfl binding to HB10I/pl2R cells (g i = 2 x 10 -1° M). Genetic structures, similar in organisation and function to the f/ operon, have been found in many pathogenic Gramnegative bacteria (Bordetella pertussis, Klebsiella pneumoniae, Haemophilis influenzae, Salmonella typhimurium, E. coli [11][12][13][14]. Each of these operons encode an outer membrane usher protein which facilitates surface localisation and correct assembly of virulence-associated surface organelles (capsules, pili, fimbriae).…”

“…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]. Polyclonal antisera was obtained from mice immunised with the peptide coupled to keyhole limpet hemocyanin with glutaraldehyde.…”

“…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]. Thus, CaflM shares 26% identity and 54% amino acid sequence similarity with the periplasmic chaperone, PapD and as with PapD stabilises the periplasmic intermediate -in this case of *Corresponding author.…”

Transcriptional regulation of the Yersinia pseudotuberculosis pH 6 antigen adhesin by two envelope‐associated components

“…MyfA and PsaA, which share 55% identity, have a region of similarity to the chaperone-binding domain of the E. coli pilus-like adhesin molecule, PapG Xu et al, 1995). MyfB and PsaB are predicted to be periplasmic chaperone proteins with high sequence similarity to the E. coli PapD family Holmgren et al, 1992;Lindberg et al, 1989). MyfC and PsaC are related to the PapC-like outermembrane usher protein family (Dodson et al, 1993).…”

Crystallization and preliminary X-ray diffraction studies of the FimC–FimH chaperone–adhesin complex from Escherichia coli

“…These highly conserved assembly systems consist of periplasmic immunoglobulin-like chaperones (Holmgren, Kuehn, Br~ind6n & Hultgren, 1992;Hultgren et al, 1993;Hung, Knight, Woods, Pinkner & Hultgren, 1996) and outer membrane associated ushers (Dodson, Jacob-Dubuisson, Striker & Hultgren, 1993). The usher molecules are large proteins that are involved in export of organelle subunits and may also function as platforms for organelle assembly.…”