Cation and sugar selectivity determinants in a novel family of transport proteins
| Autor: | C. van der Does, Gérard Leblanc, Berend Poolman, Jan Knol, Peter J. F. Henderson, Thierry Pourcher, Wei-Jun Liang, Isabelle Mus-Veteau |
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| Rok vydání: | 1996 |
| Předmět: |
Cation binding
Molecular Sequence Data Pentoses LAC PERMEASE Melibiose transport Biology Microbiology Protein Structure Secondary Bacterial Proteins Cations Amino Acid Sequence SPECIFICITY Molecular Biology Protein secondary structure chemistry.chemical_classification Permease Biological Transport Galactosides PEP group translocation STREPTOCOCCUS-THERMOPHILUS MELIBIOSE CARRIER Transport protein Amino acid Membrane protein Biochemistry chemistry ESCHERICHIA-COLI MEMBRANE-SPANNING SEGMENTS Carbohydrate Metabolism PHOSPHOTRANSFERASE SYSTEM ACIDIC RESIDUES KLEBSIELLA-PNEUMONIAE Carrier Proteins BINDING-PROPERTIES Forecasting |
| Zdroj: | Molecular Microbiology. 19:911-922 |
| ISSN: | 1365-2958 0950-382X |
| DOI: | 10.1046/j.1365-2958.1996.397949.x |
| Popis: | A new family of homologous membrane proteins that transport galactosides-pentoses-hexuronides (GPH) is described, By analysing the aligned amino acid sequences of the GPH family, and by exploiting their different specificities for cations and sugars, we have designed mutations that yield novel insights into the nature of ligand binding sites in membrane proteins, Mutants have been isolated/constructed in the melibiose transport proteins of Escherichia coli, Klebsiella pneumoniae and Salmonella typhimurium, and the lactose transport protein of Streptococcus thermophilus which facilitate uncoupled transport or have an altered cation and/or substrate specificity, Most of the mutations map in the amino-terminal region, in or near amphipathic alpha-helices II and IV, or in interhelix-loop 10-11 of the transport proteins. On the basis of the kinetic properties of these mutants, and the primary and secondary structure analyses presented here, we speculate on the cation binding pocket of this family of transporters. The regulation of the transporters through interaction with, or phosphorylation by, components of the phosphoenolpyruvate:sugar phosphotransferase system is also discussed. |
| Databáze: | OpenAIRE |
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