Insertion of carrier proteins into hydrophilic loops of the Escherichia coli lactose permease
نویسندگان
چکیده
منابع مشابه
Topography of lactose permease from Escherichia coli.
The topography of lactose permease, in native membrane vesicles and after reconstitution of the purified protein into proteoliposomes, has been investigated by labeling the membrane-embedded portions of the protein using photoactivatable, hydrophobic reagents and by labeling the exposed portions of the protein with water-soluble, electrophilic reagents. Some sites of modification have been loca...
متن کاملUnraveling the mechanism of the lactose permease of Escherichia coli.
We studied the effect of pH on ligand binding in wild-type lactose permease or mutants in the four residues-Glu-269, Arg-302, His-322, and Glu-325-that are the key participants in H(+) translocation and coupling between sugar and H(+) translocation. Although wild-type permease or mutants in Glu-325 and Arg-302 exhibit marked decreases in affinity at alkaline pH, mutants in either His-322 or Glu...
متن کاملIntermolecular thiol cross-linking via loops in the lactose permease of Escherichia coli.
Previous experiments using intermolecular thiol cross-linking to determine surface-exposed positions in the transmembrane helices of the lactose permease suggest that only positions accessible from the aqueous phase are susceptible to cross-linking. This approach is now extended to most of the remaining positions in the molecule. Of an additional 143 single-Cys mutants studied, homodimer format...
متن کاملStructure and mechanism of the lactose permease of Escherichia coli.
Membrane transport proteins that transduce free energy stored in electrochemical ion gradients into a concentration gradient are a major class of membrane proteins. We report the crystal structure at 3.5 angstroms of the Escherichia coli lactose permease, an intensively studied member of the major facilitator superfamily of transporters. The molecule is composed of N- and C-terminal domains, ea...
متن کاملSugar recognition by the lactose permease of Escherichia coli.
Biochemical, luminescence and mass spectroscopy approaches indicate that Trp-151 (helix V) plays an important role in hydrophobic stacking with the galactopyranosyl ring of substrate and that Glu-269 (helix VIII) is essential for substrate affinity and specificity. The x-ray structure of the lactose permease (LacY) with bound substrate is consistent with these conclusions and suggests that a po...
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ژورنال
عنوان ژورنال: Biochimica et Biophysica Acta (BBA) - Biomembranes
سال: 2002
ISSN: 0005-2736
DOI: 10.1016/s0005-2736(02)00398-x