Biosynthesis of the RNA polymerase inhibitor streptolydigin in Streptomyces lydicus: tailoring modification of 3-methyl-aspartate.

The asparaginyl-tRNA synthetase-like SlgZ and methyltransferase SlgM enzymes are involved in the biosynthesis of the tetramic acid streptolydigin in Streptomyces lydicus. Inactivation of slgZ led to a novel streptolydigin derivative. Overexpression of slgZ, slgM, or both in S. lydicus led to a considerable increase in streptolydigin production.