The biosynthesis of the streptolidine moiety in streptothricin F

Abstract

A series of arginines specifically labeled either with 13C and 15N or with 2H were synthesized and fed to Streptomyces L-1689-23. The streptothricin F isolated in each case was analyzed by either 13C or 2H NMR, respectively, in order to determine the labeling pattern obtained. From these results, it appears that arginine is metabolized to a β-ketoarginine, possibly via a pyridoxal phosphate adduct, and then via cyclization, reduction, rearrangement, and hydroxylation to the streptolidine moiety. The pathway described can also account for the formation of other known antibiotics, and for β-hydroxy-γ-amino acids, generally.