title: NtCP56, a new cysteine protease in Nicotiana tabacum L., involved in pollen grain development.
abstract: Proteinases play a critical role in developmental homeostasis and in response to environ-mental stimuli. Our present research reports that a new cysteine protease, NtCP56, is involved in the development of pollen grains in Nicotiana tabacum L. The NtCP56 gene, which encodes a protein of 361 amino acid residues with a calculated molecular mass of 40 kDa, is strongly expressed in anthers. The recombinant NtCP56 showed a high activity towards casein. Kinetic analysis revealed a K(m) of 2.20 mg ml(-1) and V(max) of 11.07 microg ml(-1) min(-1). The recombinant NtCP56 retained more than 50% of its maximum enzymatic activity from 20 degrees C to 60 degrees C with an optimum Tm range of 30-50 degrees C. The enzyme had a maximum activity at approximately pH 6.5. Suppression of the NtCP56 gene in anti-sense transgenic tobaccos resulted in the sterility of pollen grains. Our data indicated that, as a cysteine protease, NtCP56 might play an important role in pollen development.
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, PR China.
authors.forename: Xiao-mei
authors.initials: XM
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiao-meng
authors.initials: XM
authors.lastname: Lv
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Peng
authors.initials: P
authors.lastname: Sun
authors.forename: Hai
authors.initials: H
authors.lastname: Lu
authors.forename: Feng-lan
authors.initials: FL
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002523:Edible Grain / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D015971:Gene Expression Regulation, Enzymologic; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011058:Pollen / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D014026:Nicotiana / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
chemical_list: D010940:Plant Proteins; D003546:Cysteine Endopeptidases