Lactose permease: A beautiful chemiosmotic machine
نویسندگان
چکیده
منابع مشابه
The lactose permease meets Frankenstein.
The lactose permease (lac) of Escherichia coli is a paradigm for membrane transport proteins. Encoded by the lacY gene, the permease has been solubilized, purified to homogeneity, reconstituted into phospholipid vesicles and shown to catalyse the coupled translocation of beta-galactosides and H+ with a stoichiometry of unity. Circular dichroism and other spectroscopic approaches demonstrate tha...
متن کاملProton-coupled dynamics in lactose permease.
Lactose permease of Escherichia coli (LacY) catalyzes symport of a galactopyranoside and an H⁺ via an alternating access mechanism. The transition from an inward- to an outward-facing conformation of LacY involves sugar-release followed by deprotonation. Because the transition depends intimately upon the dynamics of LacY in a bilayer environment, molecular dynamics (MD) simulations may be the o...
متن کاملThermodynamics of Nanobody Binding to Lactose Permease.
Camelid nanobodies (Nbs) raised against the outward-facing conformer of a double-Trp mutant of the lactose permease of Escherichia coli (LacY) stabilize the permease in outward-facing conformations. Isothermal titration calorimetry is applied herein to dissect the binding thermodynamics of two Nbs, one that markedly improves access to the sugar-binding site and another that dramatically increas...
متن کاملTopography 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 کاملTopology of allosteric regulation of lactose permease.
Sugar transport by some permeases in Escherichia coli is allosterically regulated by the phosphorylation state of the intracellular regulatory protein, enzyme IIAglc of the phosphoenolpyruvate:sugar phosphotransferase system. A sensitive radiochemical assay for the interaction of enzyme IIAglc with membrane-associated lactose permease was used to characterize the binding reaction. The binding i...
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ژورنال
عنوان ژورنال: Biochimica et Biophysica Acta (BBA) - Bioenergetics
سال: 2012
ISSN: 0005-2728
DOI: 10.1016/j.bbabio.2012.06.012