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(GBP)，推测可以促进有机体的黏附。GbpA、GbpB和Gbpc已被鉴定和表征；然而，葡聚糖与细菌细胞表面的黏附机制尚不清楚。我们使用GTF和/或GBP缺陷突变体来研究gbpc在变形链球菌依赖蔗糖的黏附中的作用。他们的野生菌株MT8148和A GbpA缺失突变菌株A1通过添加rGTFD增加了蔗糖依赖的细胞对A玻璃表面的黏附。然而，缺乏gbpc的突变株c1在添加gbpc后细胞黏附能力没有发生变化。此外，rGbpC与rGTFD合成的葡聚糖的结合力显著高于rGTFC和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，在蔗糖依赖的黏附中起着关键作用。

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.