Analysis of the Interaction between the Global Regulator Mlc and EIIBGlc of the Glucose-specific Phosphotransferase System in Escherichia coli

Abstract

Mlc is a global regulator acting as a transcriptional repressor for several genes and operons ofEscherichia coli encoding sugar-metabolizing enzymes and uptake systems. The repressing activity of Mlc is inactivated by binding to the dephosphorylated form of EIICBGlc (PtsG), which is formed during the transport of glucose. Here, we demonstrate that EIIBGlc, the cytoplasmic domain of PtsG, alone is sufficient to inactivate Mlc but only when EIIBGlc is attached to the membrane by a protein anchor, which can be unrelated to PtsG. Several EIIBGlc mutants, which were altered in and around the phosphorylation site (Cys-421) of EIIBGlc, were tested for their ability to bind Mlc and to affect transcriptional repression by Mlc. The exchange of Cys-421 with serine or aspartate still allowed binding to Mlc, and in addition, derepression became constitutive, i.e. independent of phosphoenolpyruvate-dependent phosphotransferase system (PTS) phosphorylation. Mutations were made in the surface-exposed residues in the vicinity of Cys-421 and identified Arg-424 as essential for binding to Mlc. Binding of Mlc to the EIIBGlcconstructs in membrane preparations paralleled their ability to derepress Mlc-dependent transcription in vivo. These observations demonstrate that it is not the charge change at Cys-421, produced by PTS phosphorylation, that allows Mlc binding but rather the structural change in the environment surrounding Cys-421 that the phosphorylation provokes. Native Mlc exists as a tetramer. Deleting 18 amino acids from the C-terminal removes a putative amphipathic helix and results in dimeric Mlc that is no longer able to repress. Mlc is a global regulator acting as a transcriptional repressor for several genes and operons ofEscherichia coli encoding sugar-metabolizing enzymes and uptake systems. The repressing activity of Mlc is inactivated by binding to the dephosphorylated form of EIICBGlc (PtsG), which is formed during the transport of glucose. Here, we demonstrate that EIIBGlc, the cytoplasmic domain of PtsG, alone is sufficient to inactivate Mlc but only when EIIBGlc is attached to the membrane by a protein anchor, which can be unrelated to PtsG. Several EIIBGlc mutants, which were altered in and around the phosphorylation site (Cys-421) of EIIBGlc, were tested for their ability to bind Mlc and to affect transcriptional repression by Mlc. The exchange of Cys-421 with serine or aspartate still allowed binding to Mlc, and in addition, derepression became constitutive, i.e. independent of phosphoenolpyruvate-dependent phosphotransferase system (PTS) phosphorylation. Mutations were made in the surface-exposed residues in the vicinity of Cys-421 and identified Arg-424 as essential for binding to Mlc. Binding of Mlc to the EIIBGlcconstructs in membrane preparations paralleled their ability to derepress Mlc-dependent transcription in vivo. These observations demonstrate that it is not the charge change at Cys-421, produced by PTS phosphorylation, that allows Mlc binding but rather the structural change in the environment surrounding Cys-421 that the phosphorylation provokes. Native Mlc exists as a tetramer. Deleting 18 amino acids from the C-terminal removes a putative amphipathic helix and results in dimeric Mlc that is no longer able to repress. PEP-dependent phosphotransferase system phosphoenolpyruvate histidine-containing protein of the PTS membrane-bound subunit of the glucose-specific PTS transporter encoded by ptsG integral membrane domain of EIICBGlc cytoplasmic domain of EIICBGlc soluble protein of the glucose-specific PTS transporter encoded bycrr hybrid protein between Gp8 of M13 and EIIBGlc transmembrane helice 4-morpholinepropanesulfonic acid isopropyl-β-d-thiogalactopyranoside Mlc is a global transcriptional regulator (repressor) inEscherichia coli serving several genes and operons encoding a variety of sugar-metabolizing enzymes and transport systems (1Plumbridge J. Mol. Microbiol. 1998; 27: 369-381Crossref PubMed Scopus (102) Google Scholar, 2Plumbridge J. Mol. Microbiol. 1998; 29: 1053-1063Crossref PubMed Scopus (94) Google Scholar, 3Plumbridge J. Mol. Microbiol. 1999; 33: 260-273Crossref PubMed Scopus (74) Google Scholar, 4Decker K. Plumbridge J. Boos W. Mol. Microbiol. 1998; 27: 381-390Crossref PubMed Scopus (87) Google Scholar, 5Kimata K. Tanaka Y. Inada T. Aiba H. EMBO J. 2001; 13: 3587-3595Crossref Scopus (114) Google Scholar, 6Tanaka Y. Kimata K. Inada T. Tagami H. Aiba H. Genes Cells. 1999; 268: 391-399Crossref Scopus (49) Google Scholar, 7Kim S.-Y. Nam T.-W. Shin D. Koo B.-M. Seok Y.-J. Ryu S. J. Biol. Chem. 1999; 274: 25398-25402Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar). The major target for Mlc regulation is the phosphotransferase (PTS)1-dependent transport of glucose. The expression of the genes for both of the PTS enzyme II systems capable of transporting glucose, the glucose-specific transporter (EIICBGlc = PtsG) and the less specific, so-called mannose transporter (EIIABCDMan = PtsM, ManXYZ) as well as the genes for the general components of the PTS, enzyme I, and HPr, are all controlled by Mlc. In addition to these PTS proteins, MalT, the central transcriptional activator of the maltose regulon, is subject to transcriptional control by Mlc. The maltose regulon consists of 10 genes encoding enzymes and an ABC transporter involved in the uptake and the metabolism of maltose and maltodextrins, which produce intracellular glucose and glucose-1-P. The particular feature that makes Mlc an attractive subject of study is its mode of regulation. Unlike normal prokaryotic transcriptional regulators, no low molecular weight molecule, which could act as an inducer to inactivate Mlc and prevent its binding to DNA, has been identified. The induction of Mlc-controlled genes is dependent upon the activity of the PTS, and it is the binding (sequestration) of Mlc to PtsG, when PtsG is actively transporting glucose, that inactivates Mlc (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar, 9Nam T.-W. Cho S.-H. Shin D. Kim J.-H. Jeong J.-Y. Lee J.-H. Roe J.-H. Peterkofsky A. Kang S.-O. Ryu S. Seok Y.-J. EMBO J. 2001; 20: 491-498Crossref PubMed Scopus (105) Google Scholar, 10Tanaka Y. Kimata K. Aiba H. EMBO J. 2000; 19: 5344-5352Crossref PubMed Scopus (124) Google Scholar). An analogous system, in which the activity of the signal transduction protein GlnK, is regulated by sequestration by the ammonium transporter, AmtB, has been recently described (11Coutts G. Thomas G. Blakey D. Merrick M. EMBO J. 2002; 21: 536-545Crossref PubMed Scopus (186) Google Scholar). Other examples of membrane association affecting the activity of transcription regulators are known (12Ostrovsky de Spicer P. Maloy S. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 4295-4298Crossref PubMed Scopus (113) Google Scholar, 13Qin Y. Luo Z.-Q. Smyth A. Gao P. Beck von Bodman S. Farrand S. EMBO J. 2000; 19: 5212-5221Crossref PubMed Scopus (130) Google Scholar), suggesting that this might be a general method used by bacteria to achieve cellular compartmentalization. Binding of Mlc to PtsG was shown to be dependent upon the phosphorylation state of Cys-421 in the EIIBGlc domain of PtsG. Mlc interacts with the non-phosphorylated Cys-421 form of PtsG, and phosphorylation by the PTS inhibits this binding. Deletions in PtsG that remove parts of the integral membrane EIIC domain but retain one or more transmembrane helices (TM) still allow binding of Mlc to membranes carrying these deleted PtsG in vitro and derepression of Mlc-controlled genes in vivo (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). The largest deletion studied within EIICGlc, which was still able to regulate Mlc, removed TMs numbered 1–8 (14Buhr A. Erni B. J. Biol. Chem. 1993; 268: 11599-11603Abstract Full Text PDF PubMed Google Scholar) but retained a putative ninth helix (15Lengeler J.W. Jahreis K. Wehmeier U.F. Biochim. PubMed Scopus Google Scholar) and the Erni B. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). is in several of the glucose of enzyme Erni B. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). Deletions that removed all of the domain and produced a soluble were no longer able to regulate Mlc-controlled genes (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). Nam T.-W. Cho S.-H. Shin D. Kim J.-H. Jeong J.-Y. Lee J.-H. Roe J.-H. Peterkofsky A. Kang S.-O. Ryu S. Seok Y.-J. EMBO J. 2001; 20: 491-498Crossref PubMed Scopus (105) Google Scholar) by that the soluble EIIBGlc domain with Mlc. the of the of the ninth helix and is to the binding of the soluble EIIBGlc domain to the membrane or these are of the site for Mlc. The described was to this and to to the of EIIBGlc that are in with Mlc. The of EIIBGlc is known from M. S. G. H. A. Erni B. PubMed Scopus Google Scholar). The phosphorylation Cys-421, is a and is of a by a of The amino acid residues a upon phosphorylation of Cys-421 were in this G. M. A. S. H. Erni B. PubMed Scopus Google Scholar). the binding of Mlc to PtsG is to the phosphorylation state of Cys-421, we that the to with Mlc be amino acids in this were in these amino and their Mlc binding was in vivo and in Mlc is a with the binding a at the The of the for with PtsG and is within the C-terminal a to the of Mlc for the with PtsG, C-terminal were made in Mlc. These that a form of Mlc was to bind to EIIBGlc and to regulate Mlc-controlled genes in vivo. of the used are of carrying a a J. Mol. Microbiol. 1998; 29: 1053-1063Crossref PubMed Scopus (94) Google Scholar). the and is which glucose uptake by the is and which all PTS phosphorylation. These been described J. Mol. Microbiol. 1998; 29: 1053-1063Crossref PubMed Scopus (94) Google Scholar, 3Plumbridge J. Mol. Microbiol. 1999; 33: 260-273Crossref PubMed Scopus (74) Google Scholar). H. Inada T. P. Aiba H. Mol. 1998; PubMed Scopus (54) Google Scholar) was used for membrane were as described by in Scholar). encoding Mlc with the and 18 C-terminal amino acids were the and the C-terminal or the C-terminal (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar) Mlc with as The were with in the are and a (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). The and Mlc with and 18 amino acids deleted from the and an The was described (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). was made an to to amino acids with a carrying site in with the site amino acids of was between and an to of was with and and between the of to the the hybrid proteins, one to Gp8 and the to the were and used to the of to amino acids of PtsG, and to amino acids and both a site to the EIIBGlc domain were with these and the to the and the with The for Gp8 of M13 was with and and are is to amino acids of Gp8 with a the and carrying an site in with the site of The is to the C-terminal amino acids of Gp8 with a the and a site in with site of and The was with and with of domain the Gp8 the the The control was made by the of with in with Gp8 between and was used for and the of the by was by the method as described by J. T. Scholar) the from The with the was made as described for the as from B. and with PtsG were used for membrane as described in (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar), was for binding of Mlc. EIIBGlc were from a with EIIBGlc with a C-terminal from with A. K. Erni B. J. Biol. Chem. Full Text PDF PubMed Google Scholar) and Mlc from with In vitro phosphorylation to PTS in was as described (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). Mlc, when by an molecular weight of T.-W. Cho S.-H. Shin D. Kim J.-H. Jeong J.-Y. Lee J.-H. Roe J.-H. Peterkofsky A. Kang S.-O. Ryu S. Seok Y.-J. EMBO J. 2001; 20: 491-498Crossref PubMed Scopus (105) Google Scholar). by molecular it from the as a protein of of a Nam T.-W. Cho S.-H. Shin D. Kim J.-H. Jeong J.-Y. Lee J.-H. Roe J.-H. Peterkofsky A. Kang S.-O. Ryu S. Seok Y.-J. EMBO J. 2001; 20: 491-498Crossref PubMed Scopus (105) Google Scholar) a molecular weight of Mlc and transcriptional repressor that genes J. J. Mol. Microbiol. 2001; Google their In both and Mlc, the C-terminal is to form an that of an amphipathic it that this helix might be involved in the of Mlc, analogous to the of the coli repressor S. S. von B. B. EMBO J. 1993; PubMed Scopus Google Scholar). made the or 18 C-terminal amino acids of Mlc. C-terminal and the a at their for the results of molecular with the The of the putative amphipathic helix was still able to form a the all of the helix as a The in vivo of these the is shown in and still the expression was to of the 18 amino acids of Mlc. amino acids are or The amino acids are one as the and amino acids are the of Mlc, and expression carrying and the was with encoding Mlc with an and which Mlc with and 18 amino acids deleted from the and the were in acids and were with are as the of the expression in the = of protein amino its ability to be by PtsG in membrane in was still able to bind PtsG, as the of Mlc to be for repression at Mlc-dependent operons as well as for binding of Mlc by PtsG. the of and B. B. J. Mol. Biol. 2001; PubMed Scopus Google Scholar) and used the major protein of as a membrane to the integral membrane domain of PtsG. Gp8 is as a that is during membrane to the Gp8 consists of amino acids in the amino acids the and a C-terminal of 10 amino acids in the were In the the of Gp8 was between amino acids and of PtsG, in the Gp8 was between amino acids and of PtsG The longer hybrid protein and the between the that the deletion of amino acids from PtsG a membrane-bound protein capable of the activity of Mlc the between amino acids and a soluble which regulate Mlc vivo (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). The ability of the deleted PtsG and to bind Mlc in vivo and in vitro was in vivo is the ability of to derepress the by a the of the of Mlc. In a ptsG which is the central components of the PTS HPr, and is no PTS phosphorylation that PtsG is in the form that bind Mlc. expression of in the of glucose in addition, ptsG is deleted is no PtsG, Mlc to its and the expression of the at the PtsG or membrane-bound of PtsG this expression of the (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). from in the were in derepression of the Gp8 domain by was I, of in the regulation by no PTS in no PTS in a that the was capable of binding Mlc to the membrane in vitro by as described (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). the ability of in membrane made in the to bind Mlc, Gp8 alone is to bind Mlc. with that the of PtsG and in the membrane preparations were the amino acids between and of PtsG were essential for the with Mlc, we to be it expression in vivo and Mlc in we can that only the soluble domain of PtsG, of amino acid is for binding of Mlc. it that and the of PtsG are for Mlc binding but that the membrane be it or is the between the domain of PtsG and Mlc, a of was made in the vicinity of Cys-421 the and the of the the binding of Mlc and of Mlc as repressor was and its were from in that were capable of phosphorylation or the PTS The were tested in the in which is no PTS phosphorylation. The binding of EIIBGlc to Mlc is to be and derepression of Mlc-dependent genes be at their the made and the The change of the Cys-421 to or still allowed The change of to the could the of PtsG phosphorylation and could the was it that the of the charge Cys-421 is Mlc that the change in charge at Cys-421 is not the signal for Mlc and it that the is not essential for binding Mlc. the signal to bind Mlc is by the of Cys-421, it that residues surrounding Cys-421, which are by its phosphorylation G. M. A. S. H. Erni B. PubMed Scopus Google Scholar), are for the with Mlc. we the surface-exposed residues surrounding Cys-421 to In to the at Cys-421, the change of the Arg-424 to a protein that is of genes of binding to Mlc, The to at and were still capable of Mlc, at and The of the to at this in particular to and to to the charge of were in derepression The of was tested of PTS phosphorylation which in the of the central PTS Cys-421, and expression of genes is is the for the and for all the the Cys-421 which produce in this at Cys-421 were to produce the activity in both and the Cys-421 and the were still to regulation by PTS phosphorylation, we that PTS as the Cys-421 of removed by between the of the PTS that genes are J. Mol. Microbiol. 1999; 33: 260-273Crossref PubMed Scopus (74) Google Scholar, S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). allows the between an that is in binding and a protein that The exchange of Arg-424 to or that not derepress we that at Arg-424 to that are in binding Mlc. and which were in the in The that were or in the are more or less at in Cys-421 In the activity these In of we tested the ability of the to be vitro by the general components of the of the the were is in the to and the were by and by In this can be as a that is in the Gp8 control The exchange of Arg-424 with or but not with the ability of Cys-421 to be in all to derepress the The is the exchange of with the phosphorylation in is in is and in the of phosphorylation is derepression that derepression during of was were as was the that were in Mlc and the which was in Mlc In the of we tested the ability of Mlc to bind to in membrane these the of PTS phosphorylation used in the in vivo we used The both PtsG and the general PTS In this is and binding of Mlc to membranes be the tested and bind Mlc to the membranes from this the binding of Mlc that was not in the repression in to the binding of the was by the in and and the of this binding is not at with the of the ability of membranes the to bind Mlc in vitro was with their ability to expression in vivo. The used is ptsG but all the general PTS components and was the phosphorylation of the of is a of the from Cys-421 of PtsG from residues of PTS that membranes PtsG from the dephosphorylated and are able to bind Mlc. In with in the of the soluble PTS of the membranes to PtsG and binding of Mlc (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). the Cys-421 and mutants, the of Mlc binding is in the binding of Mlc in the was as with the could that the of this is The of in the membrane preparations was the soluble EIIBGlc in and was in all the hybrid were and no of were that deleted of PtsG that retained the EIIBGlc the between the EIIBGlc and the ninth helix of were capable of binding Mlc to membranes and to derepress An of soluble EIIBGlc domain was rather at Mlc from the membranes (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar). that binding of Mlc was with the EIIBGlc domain but that of PtsG, in addition to the soluble EIIBGlc for the between and EIIBGlc, was to bind Mlc to Nam T.-W. Cho S.-H. Shin D. Kim J.-H. Jeong J.-Y. Lee J.-H. Roe J.-H. Peterkofsky A. Kang S.-O. Ryu S. Seok Y.-J. EMBO J. 2001; 20: 491-498Crossref PubMed Scopus (105) Google Scholar) a between the soluble EIIBGlc domain and Mlc by it or not the of this is the as with the EIIBGlc when it is attached to in PtsG. the of the of and the was to the EIIBGlc domain to the membrane and produce a of Mlc from its or it was of a binding we that the of is to a membrane and that it can be by the Gp8 protein from unrelated to PtsG. are several to be in to this the is the EIIBGlc not soluble derepression by binding Mlc in the soluble of EIIBGlc are in this that the between Mlc and soluble EIIBGlc is still able to bind to the target In this in vivo derepression of Mlc be a of Mlc from the as and B. B. J. Mol. Biol. 2001; PubMed Scopus Google Scholar) by Gp8 to the transcriptional to the actively in with membrane-bound transcriptional that a sequestration is not sufficient and that the of the between Mlc and EIIBGlc is in the membrane the change in Mlc, which the to the binding could be by as in the a be to affect the of Mlc with soluble that be is the of the between PtsG and Mlc, but for which we no PtsG is to be dimeric in the membrane J. K. Erni B. A. 1999; PubMed Scopus Google Scholar), soluble EIIBGlc is the by in the An altered of as with PtsG could affect the or the of its binding to Mlc as with PtsG. Mlc is a and as we the which not form a bind to PtsG. is that of are to achieve derepression of with rather 10 which is sufficient with PtsG. could that the has a for Mlc for PtsG. In addition, we that the binding of the membranes for Mlc to be that of in membranes could remove of Mlc from the could only bind (8Lee S.-J. Boos W. Bouché J.-P. Plumbridge J. EMBO J. 2000; 19: 5353-5361Crossref PubMed Scopus (121) Google Scholar, 9Nam T.-W. Cho S.-H. Shin D. Kim J.-H. Jeong J.-Y. Lee J.-H. Roe J.-H. Peterkofsky A. Kang S.-O. Ryu S. Seok Y.-J. EMBO J. 2001; 20: 491-498Crossref PubMed Scopus (105) Google Scholar, 10Tanaka Y. Kimata K. Aiba H. EMBO J. 2000; 19: 5344-5352Crossref PubMed Scopus (124) Google Scholar) that binding of Mlc to PtsG upon the phosphorylation state of Cys-421 of PtsG in Mutations of this to or which we the and of EIIBGlc, both produce expression of Mutations of serine to aspartate from M. J. J. M. PubMed Scopus Google and of to aspartate P. H. J. D. Mol. Microbiol. 2001; PubMed Scopus Google been described that produce with the of the and of the for both and as of the EIIBGlc binding Mlc the form that the charge of aspartate is not sufficient to Mlc binding and that the charge produced by phosphorylation of EIIBGlc, is sufficient to for the with Mlc. In addition, these that the of Cys-421 is not by Mlc the Cys-421 are still capable of binding Mlc. The was less in in was we the Cys-421 to be to the PTS phosphorylation of the the is with which is in the but in Cys-421 is not essential for Mlc Mlc binding to the phosphorylation state of Cys-421, and we to the amino acids are by Cys-421 phosphorylation G. M. A. S. H. Erni B. PubMed Scopus Google Scholar). Cys-421 is at the of a the and is by residues amino acids that might Mlc, we these residues to residues and the were still capable of derepression of the and capable of binding of at and a ability to at Arg-424 were and The of Arg-424 with or were in Mlc in vivo. and Erni Erni B. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar) studied and PtsG. in their were for glucose and were capable of by but to the to glucose. The of the carrying Arg-424 and in to Mlc binding The still allowed Mlc but all the Arg-424 were The at and were the PtsG, and as in the of the studied by and Erni Erni B. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar), both are for glucose with the results for the PtsG carrying the was of was still for Mlc regulation. The was not with the was only it was in in vivo. of this is that the has the of EIIBGlc in vitro the phosphorylation in vivo. from the might be by of the it not the and can not be by in The that is in vitro with the and Erni Erni B. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar) that was by The that it is for that an at is essential for Mlc binding i.e. of the at this affect Cys-421 phosphorylation. The residues and with the of with Mlc, are one of that which is from Cys-421 The of these could be and the of which we is a major for Mlc. the is still capable of Mlc, the which could be to global structural The of the of and Arg-424 upon phosphorylation, a of the G. M. A. S. H. Erni B. PubMed Scopus Google Scholar), and this change could be the signal by Mlc. shown in the of EIIBGlc, the amino Cys-421, and are at the of a formed by the of and the to M. S. G. H. A. Erni B. PubMed Scopus Google Scholar, G. M. A. S. H. Erni B. PubMed Scopus Google Scholar) which a with Mlc. from the of Arg-424 Mlc the between Mlc and PtsG be more The amino acid around Cys-421 is in of the glucose of Erni B. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). the between amino acids and around the is in both the protein of PtsG from B. or PtsG of B. not derepression of in the that in addition to the protein environment of to Mlc Mutations in the domain been that change the of PtsG transport H. Y. J. Biol. Chem. 1999; 274: Full Text Full Text PDF PubMed Scopus Google Scholar, Proc. Natl. Acad. Sci. U. S. A. 2000; PubMed Scopus Google Scholar) and affect regulation by expression of genes T. J. 2000; PubMed Scopus Google Scholar, T. J.W. Jahreis K. J. 2000; PubMed Scopus Google Scholar, J. 2000; PubMed Scopus Google Scholar). these affect be in amino acids essential for with Mlc the acids can be deleted Mlc binding. The of a between transport EIICGlc, the phosphorylation by EIIBGlc, and the around Arg-424 and between the and has been in the enzyme transporter W. H. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). for the of for of the Gp8 and for the putative in the of Mlc and Erni for the of and Aiba for the