1m74
Crystal structure of Mg-ADP-bound SecA from Bacillus subtilis
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OverviewOverview
The SecA adenosine triphosphatase (ATPase) mediates extrusion of the amino, termini of secreted proteins from the eubacterial cytosol based on cycles, of reversible binding to the SecYEG translocon. We have determined the, crystal structure of SecA with and without magnesium-adenosine diphosphate, bound to the high-affinity ATPase site at 3.0 and 2.7 angstrom resolution, respectively. Candidate sites for preprotein binding are located on a, surface containing the SecA epitopes exposed to the periplasm upon binding, to SecYEG and are thus positioned to deliver preprotein to SecYEG., Comparisons with structurally related ATPases, including superfamily I and, II ATP-dependent helicases, suggest that the interaction geometry of the, tandem motor domains in SecA is modulated by nucleotide binding, which is, shown by fluorescence anisotropy experiments to reverse an endothermic, domain-dissociation reaction hypothesized to gate binding to SecYEG.
About this StructureAbout this Structure
1M74 is a Single protein structure of sequence from Bacillus subtilis with MG, SO4 and ADP as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Nucleotide control of interdomain interactions in the conformational reaction cycle of SecA., Hunt JF, Weinkauf S, Henry L, Fak JJ, McNicholas P, Oliver DB, Deisenhofer J, Science. 2002 Sep 20;297(5589):2018-26. PMID:12242434
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