title: Identification of proteinaceous inhibitors of a cysteine proteinase (an Arg-specific gingipain) from Porphyromonas gingivalis in rice grain, using targeted-proteomics approaches.
abstract: Porphyromonas gingivalis is known to be a major etiologic agent in the onset and progression of chronic periodontitis. Among various virulence factors that this bacterium produces, Arg- and Lys-specific cysteine proteinases (gingipains) are believed to be major determinants of the pathogenicity of P. gingivalis. Here, we report on our finding that there are inhibitors of these cysteine proteinases in a rice protein fraction. Comprehensive affinity chromatography and MS analyses resulted in the identification of 17 Arg-gingipain (Rgp)-interacting proteins in the rice endosperm. Of these, four proteins (i.e., a 26 kDa globulin, a plant lipid transfer/trypsin-alpha amylase inhibitor, the RA17 seed allergen, and an alpha amylase/trypsin inhibitor) were estimated to account for 90% of the Rgp inhibitory activity in the rice protein fraction, using a two-dimensional gel system of double-layer reverse zymography. In addition, a synthetic peptide derived from an Rgp-interacting protein, cyanate hydratase, could inhibit the growth of P. gingivalis and showed inhibitory activity against both the Arg- and Lys-gingipains. These results suggest that these rice proteins may be useful as nutraceutical ingredients for the prevention and management of periodontal diseases.
authors.affiliation: Food Research Center, Niigata Agricultural Research Institute, Kamo, Niigata 959-1381, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Taiyoji
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Shitomi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Eiichi
authors.initials: E
authors.lastname: Saitoh
authors.forename: Sadami
authors.initials: S
authors.lastname: Ohtsubo
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D019587:Dietary Supplements; D015180:Electrophoresis, Gel, Two-Dimensional; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism*; D000080867:Gingipain Cysteine Endopeptidases; D006801:Humans; D007525:Isoelectric Focusing; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D012275:Oryza / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010510:Periodontal Diseases / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016966:Porphyromonas gingivalis / Q000201:enzymology* / Q000472:pathogenicity; D040901:Proteomics / Q000379:methods*
chemical_list: D018829:Adhesins, Bacterial; D004791:Enzyme Inhibitors; D000080867:Gingipain Cysteine Endopeptidases; D010455:Peptides; D010940:Plant Proteins; D003546:Cysteine Endopeptidases