title: Molecular cloning and characterization of oryzacystatin-III, a novel member of phytocystatin in rice (Oryza sativa L. japonica).
abstract: On the basis of cDNA sequences, we found that the calli of rice encodes an amino acid sequence that shares 56% and 89% identity, respectively, with oryzacystatin-I and oryzacystatin-II. This sequence differs from that of oryzacystatin-II in the N-terminal region (Gln(7)-Ala(19) in the oryzacystatin-III numbering), and this region contained a glycine residue (Gly(14)), which is evolutionarily conserved in the cystatin superfamily. We named this novel protein oryzacystatin-III. Nucleotide sequencing of the 5'-flanking region of the oryzacystatin-III gene showed that it is highly homologous to the oryzacystatin-II gene but distinct from the oryzacystatin-II locus. Oryzacystatin-III inhibited papain, ficin, and human cathepsin B. The inhibition constants for papain and ficin differ from those of oryzacystatin-I and -II, and cathepsin B activity is affected only by oryzacystatin-III, showing differences in the interaction of these inhibitors with enzymes. These data suggest that the above three inhibitors may play unique physiological roles in the regulations of rice cysteine proteinases.
authors.affiliation: Food Research Center, Niigata Agricultural Research Institute, Kamo, Japan. ootsubo@ari.pref.niigata.jp
authors.forename: Sadami
authors.initials: S
authors.lastname: Ohtsubo
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Wataru
authors.initials: W
authors.lastname: Noro
authors.forename: Masayuki
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Eiichi
authors.initials: E
authors.lastname: Saitoh
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors; D000595:Amino Acid Sequence; D001483:Base Sequence; D002401:Cathepsin B / Q000037:antagonists & inhibitors; D003001:Cloning, Molecular; D015891:Cystatins / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D018076:DNA, Complementary / Q000737:chemistry; D018744:DNA, Plant / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005361:Ficain / Q000037:antagonists & inhibitors; D006801:Humans; D008969:Molecular Sequence Data; D012275:Oryza / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry; D016415:Sequence Alignment
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015891:Cystatins; D018076:DNA, Complementary; D018744:DNA, Plant; D004791:Enzyme Inhibitors; C414604:PDZD2 protein, rat; D002401:Cathepsin B; D005361:Ficain