1pv6
Crystal structure of lactose permease
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OverviewOverview
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, each with six transmembrane, helices, symmetrically positioned within the permease. A large internal, hydrophilic cavity open to the cytoplasmic side represents the, inward-facing conformation of the transporter. The structure with a bound, lactose homolog, beta-D-galactopyranosyl-1-thio-beta-D-galactopyranoside, reveals the sugar-binding site in the cavity, and residues that play major, roles in substrate recognition and proton translocation are identified. We, propose a possible mechanism for lactose/proton symport (co-transport), consistent with both the structure and a large body of experimental data.
About this StructureAbout this Structure
1PV6 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Structure and mechanism of the lactose permease of Escherichia coli., Abramson J, Smirnova I, Kasho V, Verner G, Kaback HR, Iwata S, Science. 2003 Aug 1;301(5633):610-5. PMID:12893935
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