yhdO GENE OF Bacillus subtilis ENCODES AN ACYL-ACP ACYLTRANSFERASE.

PAOLETTI L, SCHUJMAN GE, DE MENDOZA D

San Carlos de Bariloche- Río Negro- Argentina

Congreso; XXXIX Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB). XXXII Annual Meeting. Sociedad Argentina de Biofísica (SAB); 2003

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The first step in phospholipids biosynthesis is the acylation of glycerol-3-phosphate to give phosphatidic acid, which is the precursor of all membrane phospholipids. That step has been characterized in Gram negative bacteria but the knowledge in Gram positive microorganisms is scarce. That is why we begun the study of Bacillus subtilis acyltransferases. In E. coli, the genes plsB and plsC encode for glycerolphosphate and acylglycerol phosphate acyltransferases, respectively. The analysis of B. subtilis genome revealed only one gene homologue to plsC, called yhdO, and no homologues to plsB. To study the role of yhdO, we constructed the strain LP15, which contains the sole copy of yhdO under the control of an IPTG inducible promoter. In the absence of IPTG, growth of strain LP15 stops and also does lysophospholipids and phospholipids synthesis, as determined by one-dimensional TLC. Expression of yhdO in E. coli cells allowed growth of plsC but not of plsB mutant cells. By gel shift assays we demonstrated that the promoter region of yhdO is able to bind FapR, the global regulator of fatty acid biosynthesis of Gram positive bacteria, and by Western blot assays we found that YhdO is accumulated in fapR- cells. With these results we conclude that yhdO is the only gene of B. subtilis that encodes for an acylglycerolphosphate acyltransferase, that YhdO probably also has glycerolphosphate acyltransferase activity, and that expression of yhdO gene is tightly coordinated with expression of genes involved in fatty acid biosynthesis.