2qi9 | pdb_00002qi9
ABC-transporter BtuCD in complex with its periplasmic binding protein BtuF
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Overview
BtuCD is an adenosine triphosphate-binding cassette (ABC) transporter that, translocates vitamin B12 from the periplasmic binding protein BtuF into, the cytoplasm of Escherichia coli. The 2.6 angstrom crystal structure of a, complex BtuCD-F reveals substantial conformational changes as compared, with the previously reported structures of BtuCD and BtuF. The lobes of, BtuF are spread apart, and B12 is displaced from the binding pocket. The, transmembrane BtuC subunits reveal two distinct conformations, and the, translocation pathway is closed to both sides of the membrane. Electron, paramagnetic resonance spectra of spin-labeled cysteine mutants, reconstituted in proteoliposomes are consistent with the conformation of, BtuCD-F that was observed in the crystal structure. A comparison with, BtuCD and the homologous HI1470/71 protein suggests that the structure of, BtuCD-F may reflect a posttranslocation intermediate.
About this Structure
2QI9 is a Protein complex structure of sequences from Escherichia coli with PO4, SO4, 1PE and PEG as ligands. Active as Vitamin B12-transporting ATPase, with EC number 3.6.3.33 Full crystallographic information is available from OCA.
Reference
Asymmetry in the structure of the ABC transporter-binding protein complex BtuCD-BtuF., Hvorup RN, Goetz BA, Niederer M, Hollenstein K, Perozo E, Locher KP, Science. 2007 Sep 7;317(5843):1387-90. Epub 2007 Aug 2. PMID:17673622
Page seeded by OCA on Wed Nov 21 13:51:38 2007
