title: Transfer of D-phenylalanine from gramicidin S synthetase 1 to gramicidin S synthetase 2 in gramicidin S synthesis.
abstract: The transfer of phenylalanine from gramicidin S synthetase 1 (GS 1) to gramicidin S synthetase 2 (GS 2) was studied by the use of combinations of wild-type GS 1 with various GS 2s from a wild strain and gramicidin S non-producing mutant strains of Bacillus brevis Nagano. The combinations of mutant GS 2s lacking 4'-phosphopantetheine (from BI-4, C-3, E-1, and E-2) did not transfer D-phenylalanine from GS 1, although they could activate all the constituent amino acids. Other mutant GS 2s containing 4'-phosphopantetheine, except GS 2 from BII-3 (proline-activation lacking) accepted D-phenylalanine from intact GS 1. To ascertain more directly whether 4'-phosphopantetheine is involved in the transfer of D-phenylalanine from GS 1 to GS 2, pepsin digests of GS 2 that accepted [14C]phenylalanine were analyzed by Sephadex G-50 column chromatography and thin-layer chromatography (TLC). Radioactivity of [14C]phenylalanine was always associated with a peptide containing 4'-phosphopantetheine. Furthermore, the position of radioactivity was distinct from the position of 4'-phosphopantetheine on TLC after alkaline treatment or performic acid oxidation of the digests.
mesh_terms: D000591:Amino Acid Isomerases / Q000032:analysis*; D001407:Bacillus / Q000201:enzymology / Q000235:genetics; D001665:Binding Sites; D002855:Chromatography, Thin Layer; D006096:Gramicidin / Q000096:biosynthesis*; D009097:Multienzyme Complexes / Q000032:analysis*; D009154:Mutation; D010453:Peptide Synthases / Q000032:analysis*; D010649:Phenylalanine / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D009097:Multienzyme Complexes; D006096:Gramicidin; D010649:Phenylalanine; D000591:Amino Acid Isomerases; C022343:phenylalanine racemase (ATP-hydrolyzing); D010453:Peptide Synthases; C020831:gramicidin-S-synthetase 2