Biosynthesis of the vancomycin group of antibiotics: characterisation of a type III polyketide synthase in the pathway to (S)-3,5-dihydroxyphenylglycine

3,5-dihydroxyphenylacetate, a precursor for the non-proteinogenic amino acid 3,5-dihydroxyphenylglycine occurring in glycopeptide antibiotics, is determined to be catalysed by a type III polyketide synthase using malonyl-CoA as a starter unit.