Characterization of four outer membrane proteins involved in binding starch to the cell surface of Bacteroides thetaiotaomicron.

摘要: Bacteroides thetaiotaomicron , a gram-negative obligate anaerobe, utilizes polysaccharides by binding them to its cell surface and allowing cell-associated enzymes hydrolyze into digestible fragments. We use the starch utilization system as model analyze initial steps involved in polysaccharide breakdown. In recent paper, we reported that one of outer membrane proteins involved, SusG, had starch-degrading activity but was not sufficient for growth on starch. Moreover, SusG alone did have detectable activity. Previous studies shown is essential utilization. this report four other proteins, SusC through SusF, are responsible binding. Results 14 C-starch assays show SusD both contribute significant amount SusE also appears substantially Using affinity chromatography, vitro these Sus interact bind protease accessibility either or greatly increased when expressed without other. This finding supports hypothesis membrane. Evidence from additional suggests SusC, SusE, SusF exposed surface. Our results demonstrate act major surface, with enhancing SusF9s role has yet be determined, although fact protected it proteolytic attack does