FIG. 1.

(A) Results of SDS-PAGE analysis and Western blot assay of purified S. oralis ATCC 9811 rGAPDH. The sample was subjected to SDS-PAGE (5 to 15% gel) and electrotransferred onto a nitrocellulose membrane. After being blocked with Block Ace, the membrane was incubated with penta-His conjugate. Bound antibodies were visualized by employing an HRP conjugate substrate kit. (Left) SDS-PAGE gel with CBB staining; (right) Western blot. Lanes: 1, molecular mass standard proteins; 2, S. oralis ATCC 9811 rGAPDH. (B) HPLC profile and binding activity of lysyl endopeptidase-digested S. oralis rGAPDH with P. gingivalis rFimA. S. oralis rGAPDH was digested with lysyl endopeptidase and subjected to HPLC involving a Symmetry300 C₁₈ column. The elution of rGAPDH fragments was effected with a linear gradient of 0 to 60% acetonitrile at a flow rate of 1 ml/min. Fractionated fragments were collected manually by monitoring the absorbance at 210 nm. The binding activity of each peak toward P. gingivalis rFimA was measured by a BIAcore apparatus. 1, absorbance peak eluted at 41.5 min; 2, absorbance peak eluted at 46 min; 3, absorbance peak eluted at 47.5 min.