2fgj
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Crystal structure of the ABC-cassette H662A mutant of HlyB with bound ATP
OverviewOverview
The 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.
About this StructureAbout this Structure
2FGJ is a Single protein structure of sequence from Escherichia coli with ATP as ligand. Full crystallographic information is available from OCA.
ReferenceReference
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
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