4c9g

Structure of yeast mitochondrial ADP/ATP carrier isoform 2 inhibited by carboxyatractyloside (C2221 crystal form)

spinqualitylabelsall models 4c9g, resolution 2.49Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4c9g is a 1 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.49Å Ligands: BNG, CDL, CXT Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ADT2_YEAST Catalyzes the exchange of ADP and ATP across the mitochondrial inner membrane. Publication Abstract from PubMed The mitochondrial ADP/ATP carrier imports ADP from the cytosol and exports ATP from the mitochondrial matrix. The carrier cycles by an unresolved mechanism between the cytoplasmic state, in which the carrier accepts ADP from the cytoplasm, and the matrix state, in which it accepts ATP from the mitochondrial matrix. Here we present the structures of the yeast ADP/ATP carriers Aac2p and Aac3p in the cytoplasmic state. The carriers have three domains and are closed at the matrix side by three interdomain salt-bridge interactions, one of which is braced by a glutamine residue. Glutamine braces are conserved in mitochondrial carriers and contribute to an energy barrier, preventing the conversion to the matrix state unless substrate binding occurs. At the cytoplasmic side a second salt-bridge network forms during the transport cycle, as demonstrated by functional analysis of mutants with charge-reversed networks. Analyses of the domain structures and properties of the interdomain interfaces indicate that interconversion between states involves movement of the even-numbered alpha-helices across the surfaces of the odd-numbered alpha-helices by rotation of the domains. The odd-numbered alpha-helices have an L-shape, with proline or serine residues at the kinks, which functions as a lever-arm, coupling the substrate-induced disruption of the matrix network to the formation of the cytoplasmic network. The simultaneous movement of three domains around a central translocation pathway constitutes a unique mechanism among transport proteins. These findings provide a structural description of transport by mitochondrial carrier proteins, consistent with an alternating-access mechanism. Structures of yeast mitochondrial ADP/ATP carriers support a domain-based alternating-access transport mechanism.,Ruprecht JJ, Hellawell AM, Harding M, Crichton PG, McCoy AJ, Kunji ER Proc Natl Acad Sci U S A. 2014 Jan 28;111(4):E426-34. doi:, 10.1073/pnas.1320692111. Epub 2014 Jan 13. PMID:24474793 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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