The biosynthesis of nascent membrane lipoteichoic acid of Streptococcus faecium (S. faecalis ATCC 9790) from phosphatidylkojibiosyl diacylglycerol and phosphatidylglycerol.

M.C Ganfield,R.A Pieringer

doi:10.1016/s0021-9258(19)70765-0

Abstract

Phosphatidylkojibiosyl diacylglycerol functions as the acceptor of sn-glycerol 1-phosphate moieties from phosphatidylglycerol in the in vitro synthesis of the membrane lipoteichoic acid of Streptococcus faecium (S. faecalis ATCC 9790). The enzyme catalyzing this polymer-forming reaction is membrane-bound. The majority of the product is water-soluble, is excluded from Sepharose 6B, and, after longer incubations, changes to a form that co-precipitates with protein upon exposure to a denaturing agent. These properties are shared by the polyglycerol phosphate-containing membrane lipoteichoic acid isolated from whole cells of S. faecium. However, unlike the lipoteichoic acid generated in vivo, the glycerol phosphate polymer portion of the product synthesized in vitro is not substituted and, therefore, is considered a nascent lipoteichoic acid intermediate.

Highlights

IntroductionPhosphatidylkojibiosyl diacylglycerol functions as the acceptor of sn-glycerol l-phosphate moieties from phosphatidylglycerol in the in vitro synthesis of the membrane lipoteichoic acid of Stmptococcus faecium (S. faecalis ATCC 9790)
Our knowledge of the metabolic pathway leading to the synthesis of this lipoteichoic acid is limited to the transphosphatidylation reaction in which a phosphatidyl group derived from either diphosphatidylglycerol or phosphatidylglycerol is transferred to the alcohol group at the sixth carbon of the inner glucose of kojibiosyl diacylglycerol to form phosphatidylkojibiosyl diacylglycerol (2, 4) (Fig. 1)
One major interfering compound was [3H]glycerol, which is generated as a byproduct in the synthesis of both diphosphatidylglycerol and phosphatidylkojibiosyl diacylglycerol from bglycerol-3H]phosphatidylglycerol

Summary

Introduction

Phosphatidylkojibiosyl diacylglycerol functions as the acceptor of sn-glycerol l-phosphate moieties from phosphatidylglycerol in the in vitro synthesis of the membrane lipoteichoic acid of Stmptococcus faecium (S. faecalis ATCC 9790). The enzyme catalyzing this polymer-forming reaction is membrane-bound. The majority of the product is water-soluble, is excluded from Sepharose 6B, and, after longer incubations, changes to a form that co-precipitates with protein upon exposure to a denaturing agent These properties are shared by the polyglycerol phosphate-containing membrane lipoteichoic acid isolated from whole cells of S. faecium. These experiments were strengthened by an in vitro experiment of

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Conclusion