TY - JOUR
T1 - Monoglucosyldiacylglycerol, a Foreign Lipid, Can Substitute for Phosphatidylethanolamine in Essential Membrane-associated Functions in Escherichia coli
AU - Wikström, Malin
AU - Xie, Jun
AU - Bogdanov, Mikhail
AU - Mileykovskaya, Eugenia
AU - Heacock, Philip
AU - Wieslander, Åke
AU - Dowhan, William
PY - 2004/3/12
Y1 - 2004/3/12
N2 - The mechanisms by which lipid bilayer properties govern or influence membrane protein functions are little understood, but a liquid-crystalline state and the presence of anionic and nonbilayer (NB)-prone lipids seem important. An Escherichia coli mutant lacking the major membrane lipid phosphatidylethanolamine (NB-prone) requires divalent cations for viability and cell integrity and is impaired in several membrane functions that are corrected by introduction of the "foreign" NB-prone neutral glycolipid α-monoglucosyldiacylglycerol (MGlcDAG) synthesized by the MGlcDAG synthase from Acholeplasma laidlawii. Dependence on Mg2+ was reduced, and cellular yields and division malfunction were greatly improved. The increased passive membrane permeability of the mutant was not abolished, but protein-mediated osmotic stress adaptation to salts and sucrose was recovered by the presence of MGlcDAG. MGlcDAG also restored tryptophan prototrophy and active transport function of lactose permease, both critically dependent on phosphatidylethanolamine. Three mechanisms can explain the observed effects: NB-prone MGlcDAG improves the quenched lateral pressure profile across the bilayer; neutral MGlcDAG dilutes the high anionic lipid surface charge; MGlcDAG provides a neutral lipid that can hydrogen bond and/or partially ionize. The reduced dependence on Mg2+ and lack of correction by high monovalent salts strongly support the essential nature of the NB properties of MGlcDAG.
AB - The mechanisms by which lipid bilayer properties govern or influence membrane protein functions are little understood, but a liquid-crystalline state and the presence of anionic and nonbilayer (NB)-prone lipids seem important. An Escherichia coli mutant lacking the major membrane lipid phosphatidylethanolamine (NB-prone) requires divalent cations for viability and cell integrity and is impaired in several membrane functions that are corrected by introduction of the "foreign" NB-prone neutral glycolipid α-monoglucosyldiacylglycerol (MGlcDAG) synthesized by the MGlcDAG synthase from Acholeplasma laidlawii. Dependence on Mg2+ was reduced, and cellular yields and division malfunction were greatly improved. The increased passive membrane permeability of the mutant was not abolished, but protein-mediated osmotic stress adaptation to salts and sucrose was recovered by the presence of MGlcDAG. MGlcDAG also restored tryptophan prototrophy and active transport function of lactose permease, both critically dependent on phosphatidylethanolamine. Three mechanisms can explain the observed effects: NB-prone MGlcDAG improves the quenched lateral pressure profile across the bilayer; neutral MGlcDAG dilutes the high anionic lipid surface charge; MGlcDAG provides a neutral lipid that can hydrogen bond and/or partially ionize. The reduced dependence on Mg2+ and lack of correction by high monovalent salts strongly support the essential nature of the NB properties of MGlcDAG.
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U2 - 10.1074/jbc.M310183200
DO - 10.1074/jbc.M310183200
M3 - Article
C2 - 14688287
AN - SCOPUS:1642396318
SN - 0021-9258
VL - 279
SP - 10484
EP - 10493
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 11
ER -