N-terminal halves of gramicidin S synthetase 1, and tyrocidine synthetase 1 as novel members of firefly luciferase family.

It was found, by computer-assisted homology search, that the N-terminal halves of gramicidin S synthetase 1 and tyrocidine synthetase 1 are homologous with beetle luciferases and plant 4-coumarate:CoA ligases. The comparison of the reactions catalyzed by these enzymes showed that they are involved in similar reactions; the adenylation of their substrates and the formation of thiolester. Structural and functional implication of the sequence homology and molecular evolution of these proteins are discussed.