Isolation and characterization of a low-molecular-weight immunoglobulin-binding protein from Yersinia pseudotuberculosis

Abstract

A low-molecular-weight immunoglobulin-binding protein (IBP) bound with the cell envelope has been isolated from Yersinia pseudotuberculosis cells and partially characterized. This IBP is a hydrophilic protein with a high polarity index of 55.3%. The molecular weight of the protein has been determined by MALDI-TOF mass spectrometry as 14.3 kD. CD spectroscopy showed that the IBP has high contents of the beta-structure and random coil structure. The IBP contains glycine as the N-terminal amino acid. The protein can be stored for a long time at acidic pH values but aggregates and loses activity at alkaline and neutral pH. The IBP binds rabbit IgG with optimum at pH of 6.0-7.5. The IBP interacts with IgG molecule in the Fc-fragment region. The protein retains activity after heating at 100 degrees C in the presence of SDS.

MALDI-ToF mass spectrometric analysis for the identification of plague, cholera, and tularemia causative agents

“…Using this technology, the studies of peculiarities of chemical structure and lipopolysac charide modifications in causative agents of plague (Y. pestis) [25] and intestinal yersiniosis (Y. entero colitica) [26], pseudotuberculosis causative agent (Y. pseudotuberculosis) proteins [27] were conducted.…”