The function of galactosyl phosphorylpolyprenol in biosynthesis of lipoteichoic acid in <em>Bacillus coagulans</em>.

Incubation of UDP-[¹⁴C]galactose with membranes of Bacitillus coagulans led to the formation of a radioactive glycolipid, which was tentatively characterized as β-galactosyl phosphorylpolyprenol (Gal-P-prenol) on the basis of its chromatographic behavior and data from structural analysis of its sugar 1-phosphate moiety. The sugar moiety of [¹⁴C]Gal-P-prenol was shown to be incorporated into a membrane-bound polymer, which coincided with the diacyl form of lipoteichoic acid in its chromatographic behavior on columns of Sephacryl S-300, DEAE-Sephacel and octyl-Sepharose. Hydrogen fluoride hydrolysis of the polymer afforded an α-galactoside identical with Gal(α1 → 2)Gro obtained from lipoteichoic acids. The incorporation of galactose residues from [¹⁴C]Gal-P-prenol into the polymer was greatly enhanced by exogenous lipoteichoic acids, especially of the diacyl and monoacyl forms. The optimal pH and metal concentration for the Gal-P-prenol formation, respectively, were found to be 8.4 and 10 mM (MgCl₂), whereas those for the transfer of galactose from this lipid intermediate to polymer were 4.5 and 16 mM (CaCl₂). The above results lead to the conclusion that Gal-P-prenol serves as the direct galactosyl donor in the synthesis of lipoteichoic acids in B. coagulans. [ABSTRACT FROM AUTHOR]