title: Carbohydrate transporters of the bacterial phosphoenolpyruvate: sugar phosphotransferase system (PTS).
abstract: The glucose transporter of Escherichia coli couples translocation with phosphorylation of glucose. The IICB(Glc) subunit spans the membrane eight times. Split, circularly permuted and cyclized forms of IICB(Glc) are described. The split variant was 30 times more active when the two proteins were encoded by a dicistronic mRNA than by two genes. The stability and activity of circularly permuted forms was improved when they were expressed as fusion proteins with alkaline phosphatase. Cyclized IICB(Glc) and IIA(Glc) were produced in vivo by RecA intein-mediated trans-splicing. Purified, cyclized IIA(Glc) and IICB(Glc) had 100% and 30% of wild-type glucose phosphotransferase activity, respectively. Cyclized IIA(Glc) displayed increased stability against temperature and GuHCl-induced unfolding.
authors.affiliation: Departement für Chemie und Biochemie, Universität Bern, CH-3012, Bern, Switzerland
authors.forename: C
authors.initials: C
authors.lastname: Siebold
authors.forename: K
authors.initials: K
authors.lastname: Flükiger
authors.forename: R
authors.initials: R
authors.lastname: Beutler
authors.forename: B
authors.initials: B
authors.lastname: Erni
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D009154:Mutation; D010728:Phosphoenolpyruvate / Q000737:chemistry* / Q000378:metabolism*; D010766:Phosphorylation; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013696:Temperature; D013997:Time Factors; D014158:Transcription, Genetic
chemical_list: D002241:Carbohydrates; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D010728:Phosphoenolpyruvate