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

Biochemistry. 1993 Apr 13;32(14):3778-82. doi: 10.1021/bi00065a033.


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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Caprylates / metabolism
  • DNA, Bacterial / chemistry
  • Deoxyribonuclease HindIII / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / growth & development*
  • Molecular Sequence Data
  • Mutation*
  • Polymerase Chain Reaction
  • Thioctic Acid / biosynthesis*
  • Thioctic Acid / chemistry
  • Thioctic Acid / genetics


  • Caprylates
  • DNA, Bacterial
  • Thioctic Acid
  • Deoxyribonuclease HindIII
  • octanoic acid