nad-independent l-lactate dehydrogenase is required for l-lactate utilization in pseudomonas stutzeri sdmnad-independent l-lactate脱氢酶需要l-lactate利用假单胞菌stutzeri长效磺胺.pdfVIP

NAD-Independent L-Lactate Dehydrogenase Is Required for L-Lactate Utilization in Pseudomonas stutzeri SDM 1,2. 1. 1,2 1 1 1 1,2 Chao Gao , Tianyi Jiang , Peipei Dou , Cuiqing Ma *, Lixiang Li , Jian Kong , Ping Xu * 1 State Key Laboratory of Microbial Technology, Shandong University, Jinan, People’s Republic of China, 2 State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People’s Republic of China Abstract Background: Various Pseudomonas strains can use L-lactate as their sole carbon source for growth. However, the L-lactate- utilizing enzymes in Pseudomonas have never been identified and further studied. Methodology/Principal Findings: An NAD-independent L-lactate dehydrogenase (L-iLDH) was purified from the membrane fraction of Pseudomonas stutzeri SDM. The enzyme catalyzes the oxidation of L-lactate to pyruvate by using FMN as cofactor. After cloning its encoding gene (lldD), L-iLDH was successfully expressed, purified from a recombinant Escherichia coli strain, and characterized. An lldD mutant of P. stutzeri SDM was constructed by gene knockout technology. This mutant was unable to grow on L-lactate, but retained the ability to grow on pyruvate. Conclusions/Significance: It is proposed that L-iLDH plays an indispensable function in Pseudomonas L-lactate utilization by catalyzing the conversion of L-lactate into pyruvate. Citation: Gao C, Jiang T, Dou P, Ma C, Li L, et al. (2012) NAD-Independent L-Lactate Dehydrogenase Is Required for L-Lactate Utilization in Pseudomonas stutzeri SDM. PLoS ONE 7(5): e36519. doi:10.1371/journal.pone.0036519 Editor: Ivo G. Boneca, Institut Pasteur Paris, France Rec