A comprehensive survey on isoleucine biosynthesis pathways in seven epidemic Leptospira interrogans reference strains of China

作者：Zou, Ying; Guo, Xiaokui; Picardeau, Mathieu; Xu, Hai; Zhao, Guoping^*

来源：FEMS Microbiology Letters, 2007, 269(1): 90-96.

DOI：10.1111/j.1574-6968.2006.00608.x

• Leptospira interrogans
• isoleucine biosynthesis
• pyruvate pathway

Previous studies have indicated that different species of Leptospira synthesize isoleucine via either pyruvate and/or threonine pathways. Seven epidemic Leptospira interrogans reference strains from China belonging to different serovars, together with three saprophytic strains of Leptospira biflexa and Leptospira meyeri, were analysed. The isoleucine biosynthesis properties were studied firstly by measuring the key enzymes of the two pathways, citramalate synthase (CimA, CE4.1.3.-) and threonine deaminase (IlvA, CE4.2.1.16), from cell extracts of the bacteria. Meanwhile, alpha-isopropylmalate synthase (LeuA, CE4.2.1.12), the key enzyme of leucine biosynthesis, was also measured as a control. It was found that all L. interrogans strains synthesized isoleucine via the pyruvate pathway exclusively, but L. biflexa and L. meyeri used both pathways. Dot-Blot and PCR amplification of both cimA and ilvA genes in the corresponding strains provided additional evidence consistent with the data of enzymatic assays. Although it is evident that leptospires' isoleucine biosynthesis may preferentially adapt either to the pyruvate pathway exclusively for pathogens or to the combination of both pyruvate and threonine pathways for saprophytes, broader sampling with careful genomospecies identification is needed for a solid conclusion.

• 出版日期2007-4
• 单位遗传工程国家重点实验室; 复旦大学; 中国科学院上海生命科学研究院; 上海交通大学; 上海人类基因组研究中心; 山东大学; 微生物技术国家重点实验室