2onr
From Proteopedia
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Crystal structure of A. fulgidus periplasmic binding protein ModA with bound molybdate
Overview
ATP-binding cassette (ABC) transporter proteins carry diverse substrates, across cell membranes. Whereas clinically relevant ABC exporters are, implicated in various diseases or cause multidrug resistance of cancer, cells, bacterial ABC importers are essential for the uptake of nutrients, including rare elements such as molybdenum. A detailed understanding of, their mechanisms requires direct visualization at high resolution and in, distinct conformations. Our recent structure of the multidrug ABC exporter, Sav1866 has revealed an outward-facing conformation of the transmembrane, domains coupled to a closed conformation of the nucleotide-binding, domains, reflecting the ATP-bound state. Here we present the 3.1 A crystal, structure of a putative molybdate transporter (ModB(2)C(2)) from, Archaeoglobus fulgidus in complex with its binding protein (ModA). Twelve, transmembrane helices of the ModB subunits provide an inward-facing, conformation, with a closed gate near the external membrane boundary. The, ATP-hydrolysing ModC subunits reveal a nucleotide-free, open conformation, whereas the attached binding protein aligns the substrate-binding cleft, with the entrance to the presumed translocation pathway. Structural, comparison of ModB(2)C(2)A with Sav1866 suggests a common alternating, access and release mechanism, with binding of ATP promoting an, outward-facing conformation and dissociation of the hydrolysis products, promoting an inward-facing conformation.
About this Structure
2ONR is a Single protein structure of sequence from Archaeoglobus fulgidus with NO3, MG and MOO as ligands. Full crystallographic information is available from OCA.
Reference
Structure of an ABC transporter in complex with its binding protein., Hollenstein K, Frei DC, Locher KP, Nature. 2007 Mar 8;446(7132):213-6. Epub 2007 Feb 25. PMID:17322901
Page seeded by OCA on Wed Nov 21 13:14:14 2007
