title: Biosynthesis of membrane-derived oligosaccharides: a periplasmic phosphoglyceroltransferase.
abstract: Membrane-derived oligosaccharides (MDO) are glucose-containing constituents of the periplasmic space of Escherichia coli whose biosynthesis is closely linked to the metabolism of membrane phospholipids. A periplasmic enzyme has now been discovered that catalyzes the transfer of phosphoglycerol residues between species of MDO or to certain glucose-containing model substrates such as gentiobiose (6-O-beta-D-glucopyranosyl-D-glucose). The partially purified enzyme has an apparent molecular weight of about 56,000 in gel permeation chromatography, and has an absolute requirement for divalent cations, of which Mn2+ is most active. Although the transferase activity appears to be the physiological function of the enzyme, at low concentrations of acceptor, the enzyme (Enz) acts as a cyclase, with the liberation of cyclic 1(3),2-phosphoglycerol, suggesting the following mechanism: (formula, see text).
mesh_terms: D001667:Binding, Competitive; D002413:Cations, Divalent / Q000378:metabolism; D002451:Cell Compartmentation; D004187:Disaccharides / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000648:ultrastructure; D005994:Glycerophosphates / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008563:Membrane Lipids / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism*; D010770:Phosphotransferases / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D017855:Transferases (Other Substituted Phosphate Groups)
chemical_list: D002413:Cations, Divalent; D004187:Disaccharides; D005994:Glycerophosphates; D008563:Membrane Lipids; D009844:Oligosaccharides; D011135:Polysaccharides, Bacterial; C013004:glycerol 1,2 cyclic phosphate; D010770:Phosphotransferases; D017855:Transferases (Other Substituted Phosphate Groups); C037247:phosphatidylglycerol - membrane-oligosaccharide glycerophosphotransferase; C100052:gentiobiose