2ff7
From Proteopedia
The ABC-ATPase of the ABC-transporter HlyB in the ADP bound state
Structural highlights
FunctionHLYBP_ECOLX Part of the ABC transporter complex HlyBD involved in hemolysin export. Transmembrane domains (TMD) form a pore in the inner membrane and the ATP-binding domain (NBD) is responsible for energy generation. 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 PubMedThe ATP-binding cassette (ABC)-transporter haemolysin (Hly)B, a central element of a Type I secretion machinery, acts in concert with two additional proteins in Escherichia coli to translocate the toxin HlyA directly from the cytoplasm to the exterior. The basic set of crystal structures necessary to describe the catalytic cycle of the isolated HlyB-NBD (nucleotide-binding domain) has now been completed. This allowed a detailed analysis with respect to hinge regions, functionally important key residues and potential energy storage devices that revealed many novel features. These include a structural asymmetry within the ATP dimer that was significantly enhanced in the presence of Mg2+, indicating a possible functional asymmetry in the form of one open and one closed phosphate exit tunnel. Guided by the structural analysis, we identified two amino acids, closing one tunnel by an apparent salt bridge. Mutation of these residues abolished ATP-dependent cooperativity of the NBDs. The implications of these new findings for the coupling of ATP binding and hydrolysis to functional activity are discussed. A structural analysis of asymmetry required for catalytic activity of an ABC-ATPase domain dimer.,Zaitseva J, Oswald C, Jumpertz T, Jenewein S, Wiedenmann A, Holland IB, Schmitt L EMBO J. 2006 Jul 26;25(14):3432-43. Epub 2006 Jul 6. PMID:16858415[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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