Structure and Function of Mo-enzyme and its Role in Global S-Cycling

Mo酶的结构和功能及其在整体S循环中的作用

基本信息

批准号：
06453171
负责人：
YAMAZAKI Sunao
金额：
$ 5.25万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

Dimethyl sulfoxide (DMSO) respiration is known to support the cell growth of many bacteria under unaerobic conditions. The terminal enzyme of the DMSO respiration, DMSO reeducates, was studied. The gene enconding DMSO reductase, which contains a molybdenum cofactor, of the photosynthetic bacterium Rhodobacter sphaeroides f.sp.denitirficans was isolated using an oligonucleotide probe, which was synthsized based on an internal amino acid sequence of the purified enzyme. The DMSO reductase gene coded 822 amino acids (2466 base pairs, Mw 89,206) as a precursor form having a signal peptide of 42 amino acids. The deduced amino acid sequence had high homology with those of some enzymes containing a molybdenum cofactor : trimethyl amine N-oxide reductase (48%), biotin sulfoxide reductase (44%), and DMSO reductase (29%) of Escherichia coli.DMSO reductase has a broad substrate specificity. It assimilates not only DMSO but also TMAO,methionine sulfoxide, biotin sulfoxide and other synthetic alkyl aryl sulfoxides. It has extremely high stereospecificity in reduction of S-form and R-form was obtained in a optically-pure form. Stereo-selective conversion by this enzyme was of great use for organic synthesis.Global emission of dimethyl sulfide (DMS) from aquatic environmentis recentlyrevealed to be related with biological activity of reduction of sulfur compounds. Presence of DMSO and its reducing enzymes and emission of DMS in hydrosphere should be clarified further to understand the biological contribution to environment.

已知二甲基磺胺（DMSO）呼吸可支持许多细菌在非消极条件下的细胞生长。研究了DMSO呼吸的末端酶DMSO reeduceates。含有光合细菌的基因DMSO还原酶，其中包含一个属于光合细菌的钼辅因子，该基因使用寡核苷酸探针分离了基于基于纯化的Enzyme的内部氨基酸序列的合成的寡核苷酸探针。 DMSO还原酶基因编码为822个氨基酸（2466个碱基对，MW 89,206），作为具有42个氨基酸的信号肽的前体形式。推导的氨基酸序列与含有钼辅助因子的一些酶具有很高的同源性：三甲基N-氧化物还原酶（48％），硫化氧化亚硫氧化甲氧化物还原酶（44％）和DMSO还原酶（29％）的Escherichia coli.dmso coli.dmso coli.dmso较宽的次级均具有广泛的杂种。它不仅吸收了DMSO，还可以吸收TMAO，甲硫氨酸，生物素亚氧化甲氧化物和其他合成烷基芳基亚磺氧化物。它以光学纯正的形式获得了S型和R形式的降低时具有极高的立体特异性。该酶的立体选择性转化在有机合成中很有用。从最近避开的水生环境中，二甲基硫化物（DMS）的全球发射与硫化合物还原的生物学活性有关。应进一步阐明DMSO及其减少酶和DMS在水圈中的发射，以了解生物学对环境的贡献。