title: Identification and characterization of Porphyromonas gingivalis client proteins that bind to Streptococcus oralis glyceraldehyde-3-phosphate dehydrogenase.
abstract: Coaggregation of Porphyromonas gingivalis and oral streptococci is thought to play an important role in P. gingivalis colonization. Previously, we reported that P. gingivalis major fimbriae interacted with Streptococcus oralis glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and that amino acid residues 166 to 183 of GAPDH exhibited strong binding activity toward P. gingivalis fimbriae (H. Nagata, M. Iwasaki, K. Maeda, M. Kuboniwa, E. Hashino, M. Toe, N. Minamino, H. Kuwahara, and S. Shizukuishi, Infect. Immun. 77:5130-5138, 2009). The present study aimed to identify and characterize P. gingivalis components other than fimbriae that interact with S. oralis GAPDH. A pulldown assay was performed to detect potential interactions between P. gingivalis client proteins and S. oralis recombinant GAPDH with amino acid residues 166 to 183 deleted by site-directed mutagenesis. Seven proteins, namely, tonB-dependent receptor protein (RagA4), arginine-specific proteinase B, 4-hydroxybutyryl-coenzyme A dehydratase (AbfD), lysine-specific proteinase, GAPDH, NAD-dependent glutamate dehydrogenase (GDH), and malate dehydrogenase (MDH), were identified by two-dimensional gel electrophoresis followed by proteomic analysis using tandem mass spectrometry. Interactions between these client proteins and S. oralis GAPDH were analyzed with a biomolecular interaction analysis system. S. oralis GAPDH showed high affinity for five of the seven client proteins (RagA4, AbfD, GAPDH, GDH, and MDH). Interactions between P. gingivalis and S. oralis were measured by a turbidimetric method and fluorescence microscopy. RagA4, AbfD, and GDH enhanced coaggregation, whereas GAPDH and MDH inhibited coaggregation. Furthermore, the expression of luxS in P. gingivalis was upregulated by RagA4, AbfD, and GDH but was downregulated by MDH. These results indicate that the five P. gingivalis client proteins function as regulators in P. gingivalis biofilm formation with oral streptococci.
authors.affiliation: Department of Preventive Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan. kmaeda@dent.osaka-u.ac.jp
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Maeda
authors.forename: Hideki
authors.initials: H
authors.lastname: Nagata
authors.forename: Masae
authors.initials: M
authors.lastname: Kuboniwa
authors.forename: Miki
authors.initials: M
authors.lastname: Ojima
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Osaki
authors.forename: Naoto
authors.initials: N
authors.lastname: Minamino
authors.forename: Atsuo
authors.initials: A
authors.lastname: Amano
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms; D015180:Electrophoresis, Gel, Two-Dimensional; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics / Q000378:metabolism; D016966:Porphyromonas gingivalis / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D019533:Streptococcus oralis / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D009097:Multienzyme Complexes; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases