2onk | pdb_00002onk
ABC transporter ModBC in complex with its binding protein ModA
Structural highlights
Function[WTPC_ARCFU] Part of the ABC transporter complex WtpABC involved in molybdate/tungstate import. Responsible for energy coupling to the transport system (Probable). [WTPA_ARCFU] Part of the ABC transporter complex WtpABC involved in molybdate/tungstate import. Binds tungstate and molybdate. [WTPB_ARCFU] Part of the ABC transporter complex WtpABC involved in molybdate/tungstate import. Probably responsible for the translocation of the substrate across the membrane (Probable). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedATP-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 (ModB2C2) 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 ModB2C2A 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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