Identification of two putative rickettsial adhesins by proteomic analysis.
The rickettsial membrane proteins that promote their uptake by eukaryotic host cells are unknown. To identify rickettsial ligand(s) that bind host cell surface proteins, biotinylated epithelial cells were used to probe a nitrocellulose membrane containing rickettsial extracts separated by SDS-PAGE. This overlay assay revealed that two close rickettsial ligands of approximately 32-30 kDa were recognized by host cells. Both proteins were identified using high resolution 2D-PAGE coupled with mass spectrometry analysis. One protein was identified as the C-terminal extremity of rOmpB called the beta-peptide. The second interacting protein was identified as a protein of unknown function encoded by RC1281 and RP828 in Rickettsia conorii and in Rickettsia prowazekii, respectively, that shares strong similarities with other bacterial adhesins. Both proteins are highly conserved within the Rickettsia genus and might play a critical role in their pathogenicity. These data may have important implications for the development of future vaccines against rickettsial infections.
Renesto
Patricia
P
Unité des Rickettsies, CNRS UMR 6020, IFR-48, Faculté de Médecine, 27 Boulevard Jean Moulin, 13385 Marseille, France. patricia.renesto@medecine.univ-mrs.fr
Samson
Laurent
L
Ogata
Hiroyuki
H
Azza
Saïd
S
Fourquet
Patrick
P
Gorvel
Jean-Pierre
JP
Heinzen
Robert A
RA
Raoult
Didier
D
D018829:Adhesins, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D019295:Computational Biology / Q000379:methods; D015180:Electrophoresis, Gel, Two-Dimensional; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D040901:Proteomics; D012281:Rickettsia / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012283:Rickettsia prowazekii / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014709:Vero Cells
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins