Yang Y, Zhao G, Winkler M E
Department of Microbiology and Molecular Genetics, University of Texas Houston Medical School 77030-1501, USA.
FEMS Microbiol Lett. 1996 Jul 15;141(1):89-95. doi: 10.1111/j.1574-6968.1996.tb08368.x.
We isolated a miniTn10(Cmr) insertion mutant lacking pyridoxine (PN) kinase and cloned the structural gene, designated pdxK, by complementation. P1 transduction and PCR mapping and DNA sequence analysis showed that pdxK was adjacent to the crr sugar transport gene (53.95 min). Growth properties of pdxK::miniTn10 mutants supported the hypotheses that PN kinase, which also phosphorylates pyridoxal (PL) and pyridoxamine (PM) in vitro, functions solely in the B6-vitamer salvage pathway and that E. coli contains an additional PL kinase. The amino acid sequence of PdxK has signature motifs of the PfkB superfamily of carbohydrate kinases, which includes phosphofructokinases and ribokinases, and suggests that three unidentified ORFs of Salmonella typhimurium, Haemophilus influenzae, and Saccharomyces cerevisiae correspond to PN/PL/PM kinases.
我们分离出了一个缺乏吡哆醇（PN）激酶的miniTn10（Cmr）插入突变体，并通过互补克隆了结构基因，命名为pdxK。P1转导、PCR定位和DNA序列分析表明，pdxK与crr糖转运基因相邻（53.95分钟处）。pdxK::miniTn10突变体的生长特性支持了以下假设：PN激酶在体外也能磷酸化吡哆醛（PL）和吡哆胺（PM），仅在B6-维生素补救途径中起作用，并且大肠杆菌含有另一种PL激酶。PdxK的氨基酸序列具有碳水化合物激酶PfkB超家族的特征基序，该超家族包括磷酸果糖激酶和核糖激酶，这表明鼠伤寒沙门氏菌、流感嗜血杆菌和酿酒酵母中三个未鉴定的开放阅读框对应于PN/PL/PM激酶。
