Biosynthesis of enzyme-bound formylvaline and formylvalylglycine. A possible initiation complex for gramicidin A biosynthesis.

A partially purified fraction (Component I) which catalyzed the ATP-PPi exchange reaction dependent only on valine and glycine among the five constituent amino acids of gramicidin A was obtained from crude extracts of Bacillus brevis ATCC 8185, which produces both gramicidin A and tyrocidines. This fraction was found to bind valine and glycine as thioesters. The addition of a formylTHFA synthesizing system to Component I brought about the formation of Component I-bound formylvaline and formylvalylglycine.