Extracellular Secretion of the Borrelia burgdorferi Oms28 Porin and Bgp, a Glycosaminoglycan Binding Protein

摘要: Borrelia burgdorferi, the Lyme disease pathogen, cycles between its Ixodes tick vector and vertebrate hosts, adapting to vastly different biochemical environments. Spirochete gene expression as a function of temperature, pH, growth phase, host milieu is well studied, recent work suggests that regulatory networks are involved. Here, we examine release burgdorferi strain B31 proteins into conditioned medium. Spirochetes intrinsically radiolabeled at concentrations ranging from 107 109 cells per ml secreted Oms28, previously characterized outer membrane porin, RPMI As determined by immunoblotting, this secretion was not associated with blebs or cytoplasmic contamination. A similar profile obtained for spirochetes in mixtures medium serum-free Barbour-Stoenner-Kelly (BSK II) Proteomic liquid chromatography-tandem mass spectrometry analysis tryptic fragments derived culture supernatants confirmed identity 28-kDa species Oms28 revealed 26-kDa protein 5′-methylthioadenosine/S-adenosylhomocysteine nucleosidase (Pfs-2), described Bgp, glycosaminoglycan-binding protein. The more selective when logarithmic phase compared organisms stationary phase. stationary-phase released OspA, OspB, flagellin. strains B31, HB19, N40 also recovered radioimmunoprecipitation. This first report B. extracellular environment. possible roles Bgp host-pathogen interaction considered.