Please use this identifier to cite or link to this item: https://olympias.lib.uoi.gr/jspui/handle/123456789/22665
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dc.contributor.authorSahin-Toth, M.en
dc.contributor.authorFrillingos, S.en
dc.contributor.authorBibi, E.en
dc.contributor.authorGonzalez, A.en
dc.contributor.authorKaback, H. R.en
dc.date.accessioned2015-11-24T19:25:52Z-
dc.date.available2015-11-24T19:25:52Z-
dc.identifier.issn0961-8368-
dc.identifier.urihttps://olympias.lib.uoi.gr/jspui/handle/123456789/22665-
dc.rightsDefault Licence-
dc.subjectAmino Acid Sequenceen
dc.subjectBacterial Proteins/antagonists & inhibitors/*chemistry/genetics/metabolismen
dc.subjectBase Sequenceen
dc.subjectBiological Transport, Active/drug effectsen
dc.subjectCysteine/chemistryen
dc.subjectEscherichia coli/*enzymology/geneticsen
dc.subject*Escherichia coli Proteinsen
dc.subjectEthylmaleimide/pharmacologyen
dc.subjectLactose/*metabolismen
dc.subjectMembrane Transport Modulatorsen
dc.subjectMembrane Transport Proteins/antagonists &en
dc.subjectinhibitors/*chemistry/genetics/metabolismen
dc.subjectModels, Molecularen
dc.subjectMolecular Sequence Dataen
dc.subject*Monosaccharide Transport Proteinsen
dc.subjectMutagenesis, Site-Directeden
dc.subject*Protein Structure, Tertiaryen
dc.subjectRecombinant Fusion Proteins/chemistry/metabolismen
dc.subjectStructure-Activity Relationshipen
dc.subject*Symportersen
dc.subjectThiogalactosides/pharmacologyen
dc.titleThe role of transmembrane domain III in the lactose permease of Escherichia colien
heal.typejournalArticle-
heal.type.enJournal articleen
heal.type.elΆρθρο Περιοδικούel
heal.identifier.primary10.1002/pro.5560031215-
heal.identifier.secondaryhttp://www.ncbi.nlm.nih.gov/pubmed/7756986-
heal.identifier.secondaryhttp://onlinelibrary.wiley.com/store/10.1002/pro.5560031215/asset/5560031215_ftp.pdf?v=1&t=h0byx7z2&s=1a32aa86d6f2a091c77f070bd2a86037bc261fe2-
heal.languageen-
heal.accesscampus-
heal.recordProviderΠανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών Υγείας. Τμήμα Ιατρικήςel
heal.publicationDate1994-
heal.abstractDeletion of putative transmembrane helix III from the lactose permease of Escherichia coli results in complete loss of transport activity. Similarly, replacement of this region en bloc with 23 contiguous Ala, Leu, or Phe residues abolishes active lactose transport. The observations suggest that helix III may contain functionally important residues; therefore, this region was subjected to Cys-scanning mutagenesis. Using a functional mutant devoid of Cys residues (C-less permease) each residue from Tyr 75 to Leu 99 was individually replaced with Cys. Twenty-one of the 25 mutants accumulate lactose to > 70% of the steady-state exhibited by C-less permease, and an additional 3 mutants transport to lower, but significant levels (40-60% of C-less). Cys replacement for Leu 76 results in low transport activity (18% of C-less). However, when placed in the wild-type background, mutant Leu 76-->Cys exhibits highly significant rates of transport (55% of wild type) and steady-state levels of lactose accumulation (65% of wild type). Immunoblots reveal that the mutants are inserted into the membrane at concentrations comparable to wild type. Studies with N-ethylmaleimide show that mutant Gly 96-->Cys is rapidly inactivated, whereas the other single-Cys mutants are not altered significantly by the alkylating agent. Moreover, the rate of inactivation of Gly 96-->Cys permease is enhanced at least 2-fold in the presence of beta-galactopyranosyl 1-thio-beta, D-galactopyranoside. The observations demonstrate that although no residue per se appears to be essential, structural properties of helix III are important for active lactose transport.en
heal.journalNameProtein Scien
heal.journalTypepeer-reviewed-
heal.fullTextAvailabilityTRUE-
Appears in Collections:Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά) - ΙΑΤ

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