[Location of GbpC protein in Streptococcus mutans UA159]

To determine whether the glucan binding protein C (GbpC) with LPXAG motif is anchoring to the cell wall of the Streptococcus mutans UA159 (S. mutans UA159).

S. mutans UA159 GbpC C terminal gene segment was amplified by PCR, the gene sequences and the deduced amino acid sequences were analyzed. In order to locate the GbpC of S. mutans, the study isolated the wall fraction following digestion of the cell wall by N-acetylmuramidase, and the GbpC was detected by Western blot analysis. GbpC S. mutans UA159 was located with gold particles. Furthermore, the dextran-dependent aggregation (ddag) phenotype of the S. mutans UA159 under stress condition was observed.

S. mutans UA159 GbpC C-terminal LPXTG motif was replaced by LPXAG motif. GbpC was observed in the cell wall component and immunogold experiment showed that the gold particles distributed around the cell wall surface. S. mutans UA159 exhibited ddag+.

GbpC with LPXAG motif was still anchoring to the cell wall.