title: Isolation and characterization of a heme oxygenase-1 gene from Chinese cabbage.
abstract: Heme oxygenase-1 (HO1) is a heme-catabolizing enzyme induced by a variety of stress conditions. This article described the cloning and characterization of BrHO1 gene which codes for a putative HO1 from Chinese cabbage (Brassica rapa subsp. pekinensis). BrHO1 consists of three exons and encodes a protein precursor of 32.3 kD with a putative N-terminal plastid transit peptide. The amino acid sequence of BrHO1 was 84% similar to Arabidopsis counterpart HY1. The three-dimensional structure of BrHO1 showed a high degree of structural conservation compared with the known HO1 crystal structures. Phylogenetic analysis revealed that BrHO1 clearly grouped with the HO1-like sequences. The recombinant BrHO1 protein expressed in Escherichia coli was active in the conversion of heme to biliverdin IXα (BV). Furthermore, the results of subcellular localization of BrHO1 demonstrated that BrHO1 gene product was most likely localized in the chloroplasts. BrHO1 was differently expressed in all tested tissues and could be induced upon osmotic and salinity stresses, cadmium (Cd) exposure, hydrogen peroxide (H(2)O(2)), and hemin treatments. Together, the results suggested that BrHO1 plays an important role in abiotic stress responses.
authors.affiliation: College of Life Sciences, Cooperative Demonstration Laboratory of Centrifuge Technique, Nanjing Agricultural University, Nanjing, People's Republic of China.
authors.forename: Qi-Jiang
authors.initials: QJ
authors.lastname: Jin
authors.forename: Xing-Xing
authors.initials: XX
authors.lastname: Yuan
authors.forename: Wei-Ti
authors.initials: WT
authors.lastname: Cui
authors.forename: Bin
authors.initials: B
authors.lastname: Han
authors.forename: Jian-Fei
authors.initials: JF
authors.lastname: Feng
authors.forename: Sheng
authors.initials: S
authors.lastname: Xu
authors.forename: Wen-Biao
authors.initials: WB
authors.lastname: Shen
mesh_terms: D000595:Amino Acid Sequence; D001664:Biliverdine / Q000378:metabolism; D029741:Brassica rapa / Q000201:enzymology* / Q000235:genetics; D002736:Chloroplasts / Q000201:enzymology; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response; D006418:Heme / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D006427:Hemin / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D006418:Heme; D006427:Hemin; D006861:Hydrogen Peroxide; D051547:Heme Oxygenase-1; D001664:Biliverdine