Biosynthesis of TDP-L-Mycarose: The Specificity of a Single Enzyme Governs the Outcome of the Pathway

摘要

Our knowledge of the genetics for the formation of microbial secondary metabolites,including the appended unusual sugars in many cases,has grown considerably in recent years.Sequence analysis of genes found in the biosynthetic gene clusters has resulted in tentative assignments for the encoded proteins and,consequently,their putative functions in the biosynthetic pathways.However,a lack of biochemical characterization of these gene products leaves many of these assignments uncertain.Mycarose (1),a 2,6-dideoxy-L-hexose with a C-3 methyl branch,is one of the three sugar components of the macrolide antibiotic tylosin (2) produced by Streptomycesfradiae.