Biosynthesis of lipoic acid: Characterization of the lipoic acid auxotrophs Escherichia coli W1485-lip2 and JRG33-lip9

作者：Mark A. Hayden, Irene Y. Huang, Gina Iliopoulos, Marilu Orozco, Gary W. Ashley · 发表于：Biochemistry · 年份：1993 · DOI：10.1021/bi00065a033 · 被引用次数：50 · 研究领域：Biochemical Acid Research Studies、Microbial metabolism and enzyme function、Coenzyme Q10 studies and effects

The abilities of the Escherichia coli lipoic acid auxotrophs W1485-lip2 and JRG33-lip9 to grow on succinate medium in the presence of octanoate, 8-mercaptooctanoate, or 6-mercaptooctanoate have been determined. Both organisms are mutated in lipA. Neither organism can use octanoate or 6-mercaptooctanoate for production of lipoate, but the lip2 allele can use 8-mercaptooctanoate. Chromosomal DNA from the auxotrophs was amplified by PCR using primers derived from the DNA sequence of wild-type lipA and then sequenced. Both mutants contain single G/C to A/T mutations in lipA, resulting in conversion of Ser307 into Phe in W1485-lip2 and Glu195 into Lys in JRG33-lip9. These results support the hypothesis that lipA is involved in the sulfur insertion step(s) of lipoate biosynthesis and indicate that it is possible to selectively block formation of the C8-S bond through suitable mutation in lipA.