Biosynthesis of D-alanyl-lipoteichoic acid: role of diglyceride kinase in the synthesis of phosphatidylglycerol for chain elongation

Abstract

Lipophilic and hydrophilic D-alanyl-lipoteichoic acids are elongated in Lactobacillus casei by the transfer of sn-glycerol 1-phosphate units from phosphatidylglycerol to the poly(glycerophosphate) moiety of the polymer. These sn-glycerol 1phosphate units are added to the end of the poly(glycerophosphate) which is distal to the glycolipid anchor; 1,2-diglyceride results from this addition. The presence of a diglyceride kinase was suggested by the ATP-dependent phosphorylation of 1,2-diglyceride to phosphatidic acid. Inorganic phosphate was used to initiate the synthesis of lipophilic lipoteichoic acid (LTA) and the elongation of both lipophilic and hydrophilic LTA. Three observations suggest that phosphate and other anions play a role in the in vitro synthesis of LTA and its precursors. First, the conversion of 1,2-diglyceride to phosphatidic acid by diglyceride kinase was stimulated. Second, the synthesis of phosphatidylglycerol was increased. Third, the elongation of lipophilic and hydrophilic LTA was enhanced. These observations indicated that one effect of phosphate might be to enhance the utilization of 1,2-diglyceride for the synthesis of phosphatidic acid. This phospholipid is a precursor of phosphatidylglycerol, the donor of sn-glycerol 1-phosphate for elongation of LTA. Phosphatidylglycerol (PG) has been proposed to be the donor of sn-glycerol 1-phosphate (GroP) units of the poly(glycerophosphate) moiety of lipoteichoic acid (LTA) (8,9,13,14) according to the following reaction: tion would result in a cycling of the diglyceride moiety of this phospholipid.The goals of these experiments with Lactobacillus casei were to characterize further the effect of phosphate on the assembly of the LTA, PG + LTA-poly(glycerophosphate)" -* LTA-poly(glycerophosphate),+1 + 1,2-diglyceride Inorganic phosphate stimulates both the synthesis of PG and the elongation of D-alanyl-lipophilic LTA in vitro (4). These observations supported the proposed role for PG in the elongation of LTA.During the elongation of LTA, one of the reaction products is 1,2-diglyceride. Significant amounts of this diglyceride might be expected to accumulate during chain elongation. Since large amounts of diglyceride are not commonly found in bacteria (25), it is proposed that the diglyceride is either degraded or reutilized for phospholipid synthesis. A diglyceride kinase similar to that found in Escherichia coli (24) could phosphorylate the diglyceride to phosphatidic acid, a known precursor of PG (25). This phosphorylat Present address: College of Dentistry, University of Illinois at the Medical Center, Chicago, IL 60612. to determine the site of the addition of GroP units to the growing polymer, and to suggest a fate for the 1,2-diglyceride. Toluene-treated cells were used to demonstrate the synthesis and elongation of D-alanyl-LTA as well as the synthesis of various phospholipids. These cells, which are permeable to GroP, ATP, and Dalanine, synthesized LTA and phospholipids in significant amounts. For detecting diglyceride kinase, membranes were u...

Location, synthesis and function of glycolipids and polyglycerolphosphate lipoteichoic acid in Gram-positive bacteria of the phylum Firmicutes

“…Indeed, the 30 nm size of the diffuse layer in B. subtilis and the estimate that an extended LTA chain of 25 repeating units, as for instance present in S. aureus, is o 20 nm in length (Labischinski et al, 1991;Fischer, 1994) does not necessarily agree with the commonly depicted schematic representation of the Gram-positive cell wall, in which the membrane-linked LTA chain extends through the cell wall to the surface. In addition, the extension of the PGP chain by the membrane protein LtaS, which uses PG as a substrate and presumably occurs at the distal end (Taron et al, 1983), necessitates that the polymer remains closely associated with the bacterial membrane, at least during its synthesis. The introduction of D-alanines, which can also occur on fully synthesized LTA, suggests that LTA chains remain in contact with the cell membrane even after their synthesis (Fig.…”

“…1). The PGP chain is polymerized on the outside of the cell and the GroP subunits are derived from the head group of the membrane lipid phosphatidylglycerol (PG) and most likely added to the distal end of the growing chain (Taron et al, 1983;Koch et al, 1984).…”

Biosynthesis of D-alanyl-lipoteichoic acid by Lactobacillus casei: interchain transacylation of D-alanyl ester residues

“…Random distribution of D-alanyl esters. In Streptococcus faecium (3) and L. casei (23), the elongation of LTA is accomplished by the distal addition of sn-glycerol 1-phosphate from phosphatidylglycerol. This mode of addition was determined in L. casei from the gradient of label generated in the poly(glycerophosphate) chain when toluene-treated cells were incubated with [14C]glycerol 3-phosphate in the presence of 100 mM Pi.…”

Unique poly(glycerophosphate) lipoteichoic acid and the glycolipids of a Streptococcus sp. closely related to Streptococcus pneumoniae

“…Lipoteichoic acid synthesis and its relationship to membrane lipid metabolism in S. aureus (taken from [ 47 ]). Similar metabolic schemes were designed for E. faecalis [48] and L. casei [49,50]. The reactions of lipid metabolism have been reviewed in Pieringer [9].…”