Isolation of UDP-N-glycolylmuramyl-(Ala, Glu, DAP) from mycobacterium phlei

Abstract

In the cell wall of various species of Mycobateria, muramic acid is present as its Nglycolyl derivative and glucosamine as itsN-acetyl derivative [l-3] . Studies on the biosynthesis of N-acetylmuramic acid [4-61 have shown that this compound is synthesized as UDP-N-acetylmuramic acid by condensation of enolpyruvate with UDP-N-acetylglucosamine and subsequent reduction. In a previous paper we suggested [2] that N-glyco lylmuramic acid might be synthetized by the following pathway. UDP-N-acetylglucosamine + UDP-N-acetylmuramic acid -+ UDP&-glycolylmuramic acid. This pathway is in accordance with the one proposed by &hoop et al. [7] for the biosynthesis of Nglycolylneuraminic acid from N-acetylneuraminic acid. To test this hypothesis we wished to isolate from a Mycobateria a muramic acid containing precursor of the peptidoglycan and to identify its N-acyl substituent. To obtain such a precursor we used D-cycloserine, an antibiotic which inhibits the biosynthesis of Dalanyl-D-alanine, and thus leads to the accumulation of UDP-N-acylmuramyl (Ala, Glu, DAP) [8-lo] in the cells of sensitive bacteria.