High resolution structure analysis of Porphyromonas gingivalis membrane proteins in the biofilm.

本研究的目的是鉴定和鉴定与口腔链球菌GAPDH相互作用的新的牙龈卟啉单胞菌成分。通过下拉实验检测牙龈假单胞菌客户蛋白与口腔沙门氏菌重组GAPDH之间的潜在相互作用。用双向凝胶电泳法分离蛋白质，用蛋白质组串联质谱仪鉴定RagA4、AbfD、GAPDH、GdH和MDH五种蛋白质。通过生物分子相互作用分析系统分析了这些牙龈假单胞菌客户蛋白与口腔沙门氏菌GAPDH之间的相互作用。口腔沙门氏菌GAPDH与5种客户蛋白具有较高的亲和力。用比浊法和荧光显微镜测定牙龈假单胞菌与口腔沙门氏菌的共聚集性。重组RagA4、AbfD和GDH促进共聚集，而GAPDH和MDH抑制共聚集，且呈剂量依赖关系。此外，重组RagA4、AbfD和GdH可调控牙龈假单胞菌中LuxS的表达。这些结果表明，牙龈假单胞菌的5种客户膜蛋白可能是牙龈假单胞菌与口腔链球菌生物被膜形成的调节因子。

The purpose of this study is to identify and characterize new Porphyromonas gingivalis components that interact with Streptococcus oralis GAPDH. Pull-down assay was performed to detect potential interactions between P. gingivalis client proteins and S. oralis recombinant GAPDH. The proteins were separated by 2D-gel electrophoresis, and the five proteins ; RagA4, AbfD, GAPDH, GDH and MDH were identified by a proteomic-tandem mass spectrometry. Interaction between these P. gingivalis client proteins and S. oralis GAPDH was analyzed via a biomolecular interaction analysis system. S. oralis GAPDH demonstrated high affinity with five client proteins. Coaggregation between P. gingivalis and S. oralis was measured by turbidimetric method and fluorescence microscope. Recombinant RagA4, AbfD and GDH enhanced the coaggregation, whereas recombinant GAPDH and MDH inhibited in a dose-dependent manner. Furthermore, recombinant RagA4, AbfD and GDH regulated expression of luxS in P. gingivalis. These results indicate that five client membrane proteins of P. gingivalis might be regulators in P. gingivalis biofilm formation with oral streptococci.