A structural analysis of asymmetry required for catalytic activity of an ABC-ATPase domain dimer.

ABSTRACT: 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.

SUBMITTER: Zaitseva J 

PROVIDER: S-EPMC1523178 | biostudies-literature | 2006 Jul

REPOSITORIES: biostudies-literature