MOLECULAR BIOLOGICAL ANALYSIS OF SUCROSE-DEPENDENT ADHERENCE IN STREPTOCOCCUS MUTANS

变形链球菌产生多种葡聚糖结合蛋白（Gbps），这可能促进了生物体的粘附。三种Gbps， GbpA， GbpB和GbpC已被识别和表征；然而，葡聚糖与细菌细胞表面的粘附机制尚不清楚。我们使用gtf和/或gbp缺陷突变体来检测GbpC在变形链球菌的蔗糖依赖性粘附中的作用。他们的野生菌株MT8148和缺乏gbpa的突变菌株A1通过添加rGTFD增加了依赖蔗糖的细胞对玻璃表面的粘附。然而，c1，一种缺乏gbpc的突变株，在其添加后没有表现出细胞粘附的变化。此外，rGbpC与由rGTFD合成的葡聚糖的结合明显高于由rGTFC或rGTFB合成的葡聚糖。这些结果表明，GbpC通过与GTFD合成的可溶性葡聚糖结合，在蔗糖依赖性粘附中起着至关重要的作用。

STREPTOCOCCUS MUTANS PRODUCES MULTIPLE GLUCAN-BINDING PROTEINS (Gbps), WHICH PRESUMABLY PROMOTE THE ADHESION OF THE ORGANISM. THREE Gbps, GbpA, GbpB, AND GbpC HAVE BEEN IDENTIFIED AND CHARACTERIZED ; HOWEVER, THE MECHANISM OF ADHESION BETWEEN : GLUCANS AND BACTERIAL CELL SURFACE ARE UNKNOWN. WE USED GTF-AND/OR Gbp-DEFICIENT MUTANTS TO EXAMINE THE ROLE OF GbpC IN THE SUCROSE-DEPENDENT ADHERENCE OF S. MUTANS. THEIR WILD STRAIN MT8148 AND A GbpA-DEFICIENT MUTANT STRAIN A1 INCREASED SUCROSE DEPENDENT CELLULAR ADHERENCE TO A GLASS SURFACE BY THE ADDITION OF rGTFD. HOWEVER, c1, A GbpC-DEFICIENT MUTANT STRAIN, DEMONSTRATED NO CHANGES IN CELLULAR ADHESION WITH ITS ADDITION. FURTHER, THE BINDING OF rGbpC TO THE GLUCAN SYNTHESIZED BY rGTFD WAS SIGNIFICANTLY HIGHER THAN TO THE GLUCAN SYNTHESIZED BY EITHER rGTFC OR rGTFB. THESE RESULTS SUGGEST THAT GbpC PLAYS A CRUCIAL ROLE IN SUCROSE-DEPENDENT ADHERENCE BY BINDING TO THE SOLUBLE GLUCAN SYNTHESIZED BY GTFD.