Gene identification and characterization of the pyridoxine degradative enzyme 4-pyridoxic acid dehydrogenase from the nitrogen-fixing symbiotic bacterium Mesorhizobium loti MAFF303099
Gene identification and characterization of the pyridoxine degradative enzyme 4-pyridoxic acid dehydrogenase from the nitrogen-fixing symbiotic bacterium Mesorhizobium loti MAFF303099
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DOI：
10.1093/jb/mvn010
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发表时间：
2008-05-01
影响因子：
2.7
通讯作者：
Yagi, Toshiharu
中科院分区：
文献类型：
--
作者：
Ge, Fei;Yokochi, Nana;Yagi, Toshiharu
4-吡啶酸脱氢酶编码基因mlr6792在固氮共生菌中根菌MAFF303099染色体上被鉴定。该酶是维生素B-6（吡哆醇）降解途径中的第四个酶。重组酶在大肠杆菌细胞中过表达his-标签，是一种膜结合蛋白，纯化后均质化。该酶是一种分子量为59000的单体蛋白，每摩尔亚基含有1摩尔FAD。4-吡啶酸的最适pH为8.5℃，最适温度为30℃，最适Km为29 μ M。该酶是葡萄糖-甲醇-胆碱（GMC）家族蛋白，具有两种特征模式，fad结合残基，推测的活性位点组氨酸残基和可能的跨膜段。
The gene encoding 4-pyridoxic acid dehydrogenase was identified as mlr6792 in a chromosome of a nitrogen-fixing symbiotic bacterium Mesorhizobium loti MAFF303099. The enzyme is the fourth enzyme in the vitamin B-6 (pyridoxine)degradation pathway I. The recombinant enzyme with a his-tag over-expressed in Escherichia coli cells was a membrane-bound protein, and purified to homogeneity. The enzyme was a monomeric protein with a molecular weight of 59,000, and a flavoprotein containing one mole of FAD per mole of subunit. The optimum pH and temperature, and Km for 4-pyridoxic acid were pH 8.5 and 30 degrees C, and 29 mu M, respectively. The enzyme was a glucose-methanol-choline (GMC) family protein with two signature patterns, FAD-binding residues, a putative active site histidine residue and a probable transmembrane segment.