Structural Features of Glycosyltransferases Synthesizing Major Bilayer and Nonbilayer-prone Membrane Lipids inAcholeplasma laidlawii and Streptococcus pneumoniae

In membranes of Acholeplasma laidlawii two consecutively acting glucosyltransferases, the (i) α-monoglucosyldiacylglycerol (MGlcDAG) synthase (alMGS) (EC2.4.1.157) and the (ii) α-diglucosyl-DAG (DGlcDAG) synthase (alDGS) (EC 2.4.1.208), are involved in maintaining (i) a certain anionic lipid surface charge density and (ii) constant nonbilayer/bilayer conditions (curvature packing stress), respectively. Cloning of the alDGS gene revealed related uncharacterized sequence analogs especially in several Gram-positive pathogens, thermophiles and archaea, where the encoded enzyme function of a potential Streptococcus pneumoniae DGS gene (cpoA) was verified. A strong stimulation of alDGS by phosphatidylglycerol (PG), cardiolipin, or nonbilayer-prone 1,3-DAG was observed, while only PG stimulated CpoA. Several secondary structure prediction and fold recognition methods were used together with SWISS-MODEL to build three-dimensional model structures for three MGS and two DGS lipid glycosyltransferases. Two Escherichia coli proteins with known structures were identified as the best templates, the membrane surface-associated two-domain glycosyltransferase MurG and the soluble GlcNAc epimerase. Differences in electrostatic surface potential between the different models and their individual domains suggest that electrostatic interactions play a role for the association to membranes. Further support for this was obtained when hybrids of the N- and C-domain, and full size alMGS with green fluorescent protein were localized to different regions of theE. coli inner membrane and cytoplasm in vivo. In conclusion, it is proposed that the varying abilities to bind, and sense lipid charge and curvature stress, are governed by typical differences in charge (pI values), amphiphilicity, and hydrophobicity for the N- and (catalytic) C-domains of these structurally similar membrane-associated enzymes. In membranes of Acholeplasma laidlawii two consecutively acting glucosyltransferases, the (i) α-monoglucosyldiacylglycerol (MGlcDAG) synthase (alMGS) (EC2.4.1.157) and the (ii) α-diglucosyl-DAG (DGlcDAG) synthase (alDGS) (EC 2.4.1.208), are involved in maintaining (i) a certain anionic lipid surface charge density and (ii) constant nonbilayer/bilayer conditions (curvature packing stress), respectively. Cloning of the alDGS gene revealed related uncharacterized sequence analogs especially in several Gram-positive pathogens, thermophiles and archaea, where the encoded enzyme function of a potential Streptococcus pneumoniae DGS gene (cpoA) was verified. A strong stimulation of alDGS by phosphatidylglycerol (PG), cardiolipin, or nonbilayer-prone 1,3-DAG was observed, while only PG stimulated CpoA. Several secondary structure prediction and fold recognition methods were used together with SWISS-MODEL to build three-dimensional model structures for three MGS and two DGS lipid glycosyltransferases. Two Escherichia coli proteins with known structures were identified as the best templates, the membrane surface-associated two-domain glycosyltransferase MurG and the soluble GlcNAc epimerase. Differences in electrostatic surface potential between the different models and their individual domains suggest that electrostatic interactions play a role for the association to membranes. Further support for this was obtained when hybrids of the N- and C-domain, and full size alMGS with green fluorescent protein were localized to different regions of theE. coli inner membrane and cytoplasm in vivo. In conclusion, it is proposed that the varying abilities to bind, and sense lipid charge and curvature stress, are governed by typical differences in charge (pI values), amphiphilicity, and hydrophobicity for the N- and (catalytic) C-domains of these structurally similar membrane-associated enzymes. 1,2-diacyl-3-O-[α-d-glucopyranosyl-(1→2)-O-α-d-glucopyranosyl]-sn-glycerol 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate 1,2-diacyl-3-O-(α-d-glucopyranosyl)-sn-glycerol 1,2-diacyl-3-O-[α-d-glucopyranosyl-(1→2)-O-α-d-galactopyranosyl]-sn-glycerol 3-DOG, 1,3-dioleoylglycerol 1,2-diacyl-3-O-(α-d-galactopyranosyl)-sn-glycerol 1,2-diacyl-3-O-[6-O-acyl(α-d-glucopyranosyl)]-sn-glycerol 1,2-diacyl-3-O-[α-d-glucopyranosyl-(1→2)-O-(6-O-acyl-α-d-glucopyranosyl)]-sn-glycerol disugar-glycolipid synthase monosugar-glycolipid synthase phosphatidylglycerol dioleoylphosphatidylglycerol dioleoylphosphatidic acid cardiolipin glycosyltransferase green fluorescent protein amino acids open reading frame Lipid bilayer properties, important for membrane barrier and protein function, are regulated at several levels in cells. Acholeplasma laidlawii andEscherichia coli membrane lipids are metabolically designed to yield a bilayer “window” with certain features between the gel and nonbilayer phases (1Lindblom G. Brentel I. Sjölund M. Wikander G. Wieslander Å. Biochemistry. 1986; 25: 16198-16207Google Scholar, 2Morein S. Andersson A.-S. Rilfors L. Lindblom G. J. Biol. Chem. 1996; 271: 6801-6809Google Scholar). In A. laidlawii this aims at maintaining (i) a certain lipid bilayer surface charge density and (ii) a constant radius of spontaneous curvature (elastic packing stress), including similar bilayer/nonbilayer transition temperatures (1Lindblom G. Brentel I. Sjölund M. Wikander G. Wieslander Å. Biochemistry. 1986; 25: 16198-16207Google Scholar, 3Österberg F. Rilfors L. Wieslander Å. Lindblom G. Gruner S.M. Biochim. Biophys. Acta. 1995; 1257: 18-24Google Scholar). Regulation of (i) and (ii) resides mainly at the polar headgroup level (4Wieslander Å. Karlsson O.P. Curr. Top. Membr. 1997; 44: 517-540Google Scholar), whereas in E. coli curvature is regulated at the acyl chain level (2Morein S. Andersson A.-S. Rilfors L. Lindblom G. J. Biol. Chem. 1996; 271: 6801-6809Google Scholar), with more or less constant headgroup composition. The bilayer-forming glucolipid α-diglucosyldiacylglycerol (DGlcDAG)1 is one of the major lipids in the small cell wall-less A. laidlawii, the other is the nonbilayer-prone α-monoglucosyldiacylglycerol (MGlcDAG),cf. pathway below. Another pathway leads from phosphatidic acid to phosphatidylglycerol (PG). Under certain circumstances more acylated, and more nonbilayer-prone, variants of MGlcDAG and DGlcDAG, i.e. MAMGlcDAG and MADGlcDAG, respectively, are synthesized (5Andersson A.-S. Rilfors L. Lewis R.N. McElhaney R.N. Lindblom F. Biochim. Biophys. Acta. 1998; 1389: 43-49Google Scholar). A. laidlawiican only synthesize saturated acyl chains, and to still be able to adapt to membrane stress and new environments, the amounts of the two major glucolipids are strongly adjusted to maintain a functional membrane bilayer. The MGlcDAG-synthesizing enzyme alMGS (EC 2.4.1.157) ((i) above) was recently cloned (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar) and found to be a surface-associating protein with no transmembrane segments, where bilayer binding was dependent on phosphatidylglycerol and stimulated by small amounts of nonbilayer lipids. 2L. Li, submitted for publication. This seemed logical given the strong involvement of this enzyme in the lipid surface charge regulation, i.e. (i) above (8Karlsson O.P. Dahlqvist A. Vikström S. Wieslander Å. J. Biol. Chem. 1997; 272: 929-936Google Scholar). The 1,2-diacylglycerol-3-α-glucose (1 → 2)-α-glucosyl transferase (DGS) (EC 2.4.1.208) catalyzes the consecutive transfer of glucose from UDP-Glc to MGlcDAG to yield DGlcDAG (cf. (ii) above). This reaction is activated in an essential manner by certain anionic lipids and stimulated by other additives promoting nonbilayer tendencies both in vivo (1Lindblom G. Brentel I. Sjölund M. Wikander G. Wieslander Å. Biochemistry. 1986; 25: 16198-16207Google Scholar, 9Wieslander Å. Rilfors L. Lindblom G. Biochemistry. 1986; 25: 7511-7517Google Scholar) and with crude or pure enzymes in vitro (10Vikström S. Li L. Karlsson O.P. Wieslander Å. Biochemistry. 1999; 38: 5511-5520Google Scholar, 11Dahlqvist A. Nordström S. Karlsson O.P. Mannock D.A. McElhaney R.N. Wieslander Å. Biochemistry. 1995; 34: 13381-13389Google Scholar), keeping or restoring bilayer packing conditions. Furthermore, an additional modulation of the activity is achieved by certain phosphorylated metabolites, double-stranded DNA (12Vikström S. Li L. Wieslander Å. J. Biol. Chem. 2000; 275: 9296-9302Google Scholar), and by a low redox potential (7Wimley W.C. White S.H. Nat. Struct. Biol. 1996; 3: 842-848Google Scholar). Due to their small polar headgroups, nonbilayer-prone lipids of the reversed type, like MGlcDAG, make the two monolayers in a bilayer each want to curl concavely toward the water phase. This induces a curvature elastic stress (increased spontaneous curvature), with an increased chain order and a closer approach to a bilayer-nonbilayer phase transition. Similar packing features can be inferred for the major galactolipids in the membranes of chloroplasts and photosynthetic bacteria Scholar). A of and membrane proteins are by this stress, for the are known Biochemistry. 2001; Scholar), with the lipid is S. S. A. 2000; Scholar, Biochemistry. 2001; Scholar, Biochemistry. Scholar). a of is the A. laidlawii DGS is able to sense the curvature stress and by increased or of The cloned gene an enzyme from E. and the amino acid sequence and the secondary and three-dimensional structure models strongly this enzyme to similar in structure and surface association as the MGlcDAG synthase and several other glycosyltransferases. the bilayer/nonbilayer lipid and the bilayer are at the bilayer surface by the DGlcDAG revealed a new of related lipid in Gram-positive bacteria and of from Streptococcus pneumoniae this to be for of in a of to the of the and the is by certain differences in the enzyme structure A. laidlawii was in in A. Nordström S. Karlsson O.P. Mannock D.A. McElhaney R.N. Wieslander Å. Biochemistry. 1995; 34: 13381-13389Google Scholar), with acid The were and the DNA was with the pneumoniae was in at The DNA was by the cell at for the the DNA was in the DNA were on the amino acid sequence of the A. laidlawii DGlcDAG synthase (alDGS) Edman (10Vikström S. Li L. Karlsson O.P. Wieslander Å. Biochemistry. 1999; 38: 5511-5520Google Scholar). sequence was and by The and were used in a that in a DNA The were and the and The was by and used as a in a with DNA from A. The were by The DNA with size to the were and the and E. coli cells. were found by to and Scholar) with the The sequence of the DNA was both and with reaction these a was where the from A. laidlawii was cloned a and E. coli This was used for the The gene for the in S. identified with the alDGS sequence in a was by with the and to the and sequence respectively. The was a and was from The MGlcDAG and DGlcDAG were as (8Karlsson O.P. Dahlqvist A. Vikström S. Wieslander Å. J. Biol. Chem. 1997; 272: 929-936Google Scholar). was obtained from Mannock (cf. Dahlqvist A. Nordström S. Karlsson O.P. Mannock D.A. McElhaney R.N. Wieslander Å. Biochemistry. 1995; 34: 13381-13389Google and were from and from in the was in with of The were at and was at were by at E. coli were in and to a protein of by in a and three on for In the for of protein (cf. above) was to of lipid and on for The reaction was by of of or to a of in a of lipid was (1 MGlcDAG in to the and the nonbilayer-prone with DGlcDAG as of at the reaction was with of and the lipids were and by (10Vikström S. Li L. Karlsson O.P. Wieslander Å. Biochemistry. 1999; 38: 5511-5520Google Scholar, O.P. Dahlqvist A. Wieslander Å. J. Biol. Chem. Scholar). The lipid on the were and by were in A of was used as J. 1998; Scholar). N- and respectively, were cloned and with the gene for green fluorescent protein a approach on the alMGS sequence (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar) and the in E. coli and and the obtained were by DNA of the proteins were with by of E. coli lipids in vivo with (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar) and by for MGlcDAG in vitro (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar). of the variants in E. coli was by at and a a and to the alDGS and to a function for the in J. 1997; 25: Scholar) at in the and the for and was sequence were obtained from The for of the structure of the alDGS sequence were with at the of and with the secondary and three-dimensional structure models were from by several structure and and fold recognition methods and and the J. L. J. A. 2001; Scholar) at the A. L. 2001; Scholar). The the between the obtained models are from and (cf. J. L. J. A. 2001; Scholar). The from several known glycosyltransferase structures were in a similar manner and the structures with the L. J. Biol. Scholar). models of the were on the sequence and given by the the for 1997; Scholar) and the of the SWISS-MODEL for model the MGS the three protein structures of and were used as templates, while the DGS were with the two and as proteins were the models obtained from the SWISS-MODEL are were to an additional to the a were adjusted as were the of chains, a an be able to the the of the was together with the SWISS-MODEL of by of The of the models was the G. 1996; Scholar). of secondary structure of the electrostatic surface and were the M. J. 1996; Scholar). The electrostatic were on of and for protein and respectively, an of a and a of potential at Å. A radius of was used when the of the of each model were The of was from their and three and S. F. 1998; Scholar). sequence for A. laidlawii DGlcDAG synthase at with The and an amino acid sequence of the DGlcDAG synthase from A. laidlawii (alDGS) were by Edman (10Vikström S. Li L. Karlsson O.P. Wieslander Å. Biochemistry. 1999; 38: 5511-5520Google Scholar). a was used in a a DNA that was The sequence of this revealed an open reading frame of for the alDGS sequence with a potential sequence at The was is typical for A. laidlawii DNA J. McElhaney R.N. and for The found the gene was related to proteins from the The sequence to a found in in the were The A. laidlawii the gene cloned (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar) and the no sequence in and were localized to the DNA to it was that these two glycosyltransferase are to each other on the and to the of the of regions to DGS in A. new for DGS is to to to protein Streptococcus new for DGS is in a new in the and the at with the alDGS amino acid sequence several in and the were Gram-positive and were from The best a gene in with to the and from or other related an above an to the A. laidlawii one 34: Scholar, Scholar), and the are In the from S. the glucose is by a the alMGS of and were to similar enzymes in S. pneumoniae and these were to to the A. laidlawii enzyme (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar). alDGS and the of the for the of of J. 1997; the enzyme alMGS (cf. to this (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar). a typical for to in this transfer like and to a of as and are by three and two from is a gene from by a of structure to the A. in S. pneumoniae the is by sequence pneumoniae pneumoniae best found by in and at are found in Gram-positive bacteria and to the alMGS are found by in in the are of of are by three and two from is a gene from by a of structure to the A. in S. pneumoniae the is by in a new The best found by in and at are found in Gram-positive bacteria and to the alMGS are found by in in the are of of The revealed no proteins with an function, of are from recently and the S. pneumoniae gene in was by J. J. 1997; Scholar) and This protein was proposed to be involved in to and was from The and the consecutive both of the were to be involved in of the in acid or of acid to J. J. 1997; Scholar). recently that this encoded an enzyme in function to alMGS (cf. (i) in and that was This enzyme was of sequence to alMGS as the protein is to alDGS (cf. and the of with a potential alDGS a to to sequence (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar). The that the of DGS and MGS in S. pneumoniae were to each other in an was for of the in for A. laidlawii and the related and for the function of the S. pneumoniae MGS enzyme above) (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar), the gene was and to function (cf. The revealed analogs in the three are of The membrane of the major and several and J. 1997; Scholar), are enzymes the can be proposed to the with the and the (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar), the In a DGlcDAG was found with the → structure A. A. J. Biochim. Biophys. Acta. Scholar), and an with low to alDGS was found by the A. laidlawii alDGS gene in a of especially Gram-positive pathogens, and analogs in and thermophiles (cf. of these are encoded to an alMGS in an of A. from MGlcDAG, with crude cell proteins or only the no other glucose was or (10Vikström S. Li L. Karlsson O.P. Wieslander Å. Biochemistry. 1999; 38: 5511-5520Google Scholar, 11Dahlqvist A. Nordström S. Karlsson O.P. Mannock D.A. McElhaney R.N. Wieslander Å. Biochemistry. 1995; 34: 13381-13389Google Scholar). alDGS and S. pneumoniae were cloned and in E. coli and activity the function and a new lipid was synthesized by the cloned alDGS when the was with from A. laidlawii and UDP-Glc This identified as the → the as the lipid obtained from crude or DGS enzyme from A. laidlawii (10Vikström S. Li L. Karlsson O.P. Wieslander Å. Biochemistry. 1999; 38: 5511-5520Google Scholar), and several lipids J. 1998; Scholar). with or no The sequence between alDGS and the to a similar function as of the lipid and and the and were were with the anionic that the was able to the of only by the This is in with of the lipid in S. where the two major were to be (MGlcDAG) and J. S. Biophys. Scholar, J. J. Scholar), and where were in and as in A. laidlawii J. Scholar, Rilfors L. Lindblom G. G. Biochim. Biophys. Acta. 1995; Scholar). recently the gene as the S. (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar). the protein is the consecutively acting to the alDGS Furthermore, of MGlcDAG, and be achieved in a of three E. coli each of a phosphatidic acid identified by (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar) and S. J. M. W.C. White Lewis E. S. F. D.A. 2001; an of this lipid pathway can be achieved the in an in The alDGS enzyme is toward the of certain anionic and nonbilayer as as phosphorylated and the redox (7Wimley W.C. White S.H. Nat. Struct. Biol. 1996; 3: 842-848Google Scholar, S. Li L. Karlsson O.P. Wieslander Å. Biochemistry. 1999; 38: 5511-5520Google Scholar, S. Li L. Wieslander Å. J. Biol. Chem. 2000; 275: 9296-9302Google Scholar). features are to the for of the nonbilayer/bilayer packing conditions in the A. laidlawii by nonbilayer-prone (curvature elastic can be in Biochim. Biophys. Acta. Scholar, Lindblom G. Biophys. J. Scholar, M. Biol. 2001; Scholar). and for the DGlcDAG synthase from A. laidlawii and the synthase from S. pneumoniae that both enzymes to PG in a similar that only the A. laidlawii was stimulated by and strongly by the nonbilayer-prone of alDGS with the of lipid in the two lipid with one in to a to the phase of membrane lipids toward nonbilayer A. Lipid 1999; 38: Scholar). The of and was a strong stimulation of alDGS by the nonbilayer-prone of the is that to the lipid In S. pneumoniae is a major membrane and PG J. J. Scholar), as is J. J. Scholar). be that the enzyme that binding an at the membrane or that the potential from the lipid surface the (cf. in enzyme The of for toward the nonbilayer-prone that this S. pneumoniae enzyme is designed to sense packing In A. laidlawii is a between low MGlcDAG and more DGlcDAG, and amounts S. Biophys. 1986; Scholar, Wieslander Å. A. J. Scholar). in A. laidlawii is the for the cloned alDGS is in with the enzyme (10Vikström S. Li L. Karlsson O.P. Wieslander Å. Biochemistry. 1999; 38: 5511-5520Google Scholar, S. Li L. Wieslander Å. J. Biol. Chem. 2000; 275: 9296-9302Google Scholar). The differences in toward between alDGS and are to was for the alMGS and enzymes amounts (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar). these A. laidlawii and S. pneumoniae lipid certain features in their sequence for from with and structures The of and on the of the structure models with the for the N- and and differences are especially for from with and structures The of and on the of the structure models with the for the N- and and differences are especially for of is from with and structures The of and on the of the structure models with the for the N- and and differences are especially for The of is in a new the of to alDGS including the cloned with an function are the to two one the in the in and the other the of in The is the of the a (cf. and proposed the of the alDGS sequence to a of the three and to be involved in the L. J. Biol. Chem. 2000; 275: Scholar). and to be the in in the two regions with A with revealed a similar between the two A. laidlawii at (alMGS) and with (cf. and The and transmembrane I. J. Biol. 1998; DGS is with the membrane (10Vikström S. Li L. Karlsson O.P. Wieslander Å. Biochemistry. 1999; 38: 5511-5520Google Scholar, A. Andersson S. Wieslander Å. Biochim. Biophys. Acta. Scholar). the of the was found in the membrane that it with membrane in vivo J. J. 1997; Scholar). A is typical for membrane-associated proteins J. 2001; Scholar), and membrane lipid are to their anionic lipids a the alMGS enzyme especially to like alDGS a is at and as The is with a of charge features were the analogs and the from to The was the for the proteins from S. A for other was an with and a with the for the two S. pneumoniae enzymes with the A. laidlawii especially for the domains This the for the different toward of the A. laidlawii and S. pneumoniae A of structure prediction and fold recognition methods A. L. 2001; Scholar), with the J. L. J. A. 2001; Scholar), were used to the potential for and alMGS in the and A was proposed to the three-dimensional structures of the and the soluble are strongly related to The sequence were the for an in and model in The proteins and were the protein structures of and while of alDGS and were with only the two and A. J. Scholar, 2001; Scholar, S. M. Biochemistry. 2000; Scholar, J. Biol. 2001; Scholar, Curr. Struct. Biol. 2001; Scholar). A of the models and their surface charge are in and important of the models are given in the In the model structures packing and together with the of the synthase to the and these of are to to a similar low sequence The binding of alMGS to anionic (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar), the of the potential and the bilayer of the and MGlcDAG lipid strongly support the as the lipid of the enzymes. model were by sequence with proteins of known structures of to lipid membranes coli glycosyltransferase and to the of proteins to to lipids membranes. coli proteins and A. glycosyltransferase and both A. sequence were to with to each In the proposed structure of a certain alDGS or alMGS in to the structure in the the sequence were This was the for certain and especially more at the surface and by or are important in several proteins like the domains in and 1999; Scholar, M. 1996; Scholar). Furthermore, no sequence were for the structures of several proteins synthase and lipid or were by the and S. White Several differences were alDGS more and one in the two by two sequence in their in the The soluble no and MurG one in the to be the S. S. 2000; Scholar). The to at similar in the three MGS enzymes. important differences in charge and hydrophobicity between alDGS and be related to their different toward the anionic and nonbilayer similar differences between alDGS and alMGS be the for the strong stimulation of alDGS by nonbilayer-prone lipids. The N- and C-domains of alMGS a and low yield different membrane DNA these and were in of the gene for in the and coli and the N- and alMGS activity as revealed from of MGlcDAG by E. coli in as as in vitro similar to the cloned enzyme (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google Scholar). of the proteins was by at and gene conditions A membrane association in E. coli of the full size was similar to a of binding J. S. A. Scholar). The low of the protein membrane as is in the a similar to the with an to an structure A membrane of the with a strong to the cell is similar to the of the E. coli protein L. J. J. J. Biol. Chem. Scholar), and by J. 2001; Scholar). The alMGS was from the cell to the cytoplasm by a in Furthermore, the the to the E. coli membrane A. I. J. 2001; Scholar). Similar are for is found with the membrane L. J. Biol. Chem. 2000; 275: Scholar). the three variants of the MGS domains different membrane binding in vivo. E. coli membrane lipids anionic lipids to yield binding of alMGS to in binding and activity of and activity of alDGS PG (6Berg S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google by different that the cell of E. coli are in the anionic with the membrane E. J. 2000; Scholar, J. 2001; Scholar). The different in vivo binding of the alMGS to charge is to the differences for and membrane lipid domains in proteins J. Biol. Chem. 2001; 276: Scholar). The a between and J. Biol. Chem. 2001; 276: Scholar). differences between the alDGS and alMGS N- and C-domains were revealed and the and are both more similar to alMGS in this this the and of the as is in and S. Edman M. Li L. Wikström M. Wieslander Å. J. Biol. Chem. 2001; 276: 22056-22063Google the and the with it is that these lipid are with the membrane lipid the of the bilayer packing and the be to the by the N- and C-domains of these enzymes are and as from and This is to the and membrane domains in The different amounts of and on the enzyme and support that lipid surface charge and curvature elastic packing stress the and the between the N- and This can be to the interactions of the soluble and lipid and to other like and