Tavares I M, Jolly L, Pompeo F, Leitão J H, Fialho A M, Sá-Correia I, Mengin-Lecreulx D
Centro de Engenharia Biológica e Química, Instituto Superior Técnico, 1049-001 Lisbon, Portugal.
J Bacteriol. 2000 Aug;182(16):4453-7. doi: 10.1128/JB.182.16.4453-4457.2000.
A search for a potential algC homologue within the Pseudomonas aeruginosa PAO1 genome database has revealed an open reading frame (ORF) of unknown function, ORF540 in contig 54 (July 1999 Pseudomonas genome release), that theoretically coded for a 445-amino-acid-residue polypeptide (I. M. Tavares, J. H. Leitão, A. M. Fialho, and I. Sá-Correia, Res. Microbiol. 150:105-116, 1999). The product of this gene is here identified as the phosphoglucosamine mutase (GlmM) which catalyzes the conversion of glucosamine-6-phosphate to glucosamine-1-phosphate, an essential step in the formation of the cell wall precursor UDP-N-acetylglucosamine. The P. aeruginosa gene has been cloned into expression vectors and shown to restore normal peptidoglycan biosynthesis and cell growth of a glmM Escherichia coli mutant strain. The GlmM enzyme from P. aeruginosa has been overproduced to high levels and purified to homogeneity in a six-histidine-tagged form. Beside its phosphoglucosamine mutase activity, the P. aeruginosa enzyme is shown to exhibit phosphomannomutase and phosphoglucomutase activities, which represent about 20 and 2% of its GlmM activity, respectively.
在铜绿假单胞菌PAO1基因组数据库中搜索潜在的algC同源物时，发现了一个功能未知的开放阅读框（ORF），即重叠群54中的ORF540（1999年7月假单胞菌基因组发布），理论上它编码一个445个氨基酸残基的多肽（I.M.塔瓦雷斯、J.H.莱唐、A.M.菲亚略和I.萨-科雷亚，《微生物学研究》150:105-116，1999年）。该基因的产物在此被鉴定为磷酸葡糖胺变位酶（GlmM），它催化6-磷酸葡糖胺转化为1-磷酸葡糖胺，这是细胞壁前体UDP-N-乙酰葡糖胺形成过程中的关键步骤。铜绿假单胞菌基因已被克隆到表达载体中，并显示可恢复glmM大肠杆菌突变株的正常肽聚糖生物合成和细胞生长。铜绿假单胞菌的GlmM酶已大量过量表达，并以带有六个组氨酸标签的形式纯化至同质。除了其磷酸葡糖胺变位酶活性外，铜绿假单胞菌的这种酶还显示出磷酸甘露糖变位酶和磷酸葡萄糖变位酶活性，分别约占其GlmM活性的20%和2%。
