2FF7: The Abc-Atpase Of The Abc-Transporter Hlyb In The Adp Bound State

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.
PDB ID: 2FF7Download
MMDB ID: 40839
PDB Deposition Date: 2005/12/19
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.6  Å
Source Organism:
Similar Structures:
Biological Unit for 2FF7: monomeric; determined by author
Molecular Components in 2FF7
Label Count Molecule
Protein (1 molecule)
Alpha-hemolysin Translocation Atp-binding Protein Hlyb
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB