THE FEMR315 GENE FROM STAPHYLOCOCCUS-AUREUS, THE INTERRUPTION OF WHICH RESULTS IN REDUCED METHICILLIN RESISTANCE, ENCODES A PHOSPHOGLUCOSAMINE MUTASE

The femR315 gene was recently identified by Tn551 insertional mutagene sis as one of the new auxiliary genes, the alteration of which resulte d in a drastically reduced methicillin resistance of the Staphylococcu s aureus strain COL. femR315 (also known as femI) theoretically encode d a protein of 451 amino acids showing significant amino acid sequence homology with phosphoglucomutases and similar enzymes catalyzing the isomerization of hexoses and hexosamine phosphates (S. Wu, H. de Lenca stre, A. Sali, and A. Tomasz, Microb. Drug Resist, 2:277-286, 1996), W e describe here the overproduction and purification of the FemR315 pro tein as well as its identification as the phosphoglucosamine mutase wh ich catalyzes the formation of glucosamine-1-phosphate from glucosamin e-6-phosphate, the first step in the reaction sequence leading to the essential peptidoglycan precursor UDP-N-acetylglucosamine. On the basi s of these findings, we propose to change the names femR315 and femD t o the functionally more appropriate name glmM.