2QI9

ABC-transporter BtuCD in complex with its periplasmic binding protein BtuF

Summary for 2QI9

• Entry DOI: 10.2210/pdb2qi9/pdb
• Descriptor: Vitamin B12 import system permease protein btuC, Vitamin B12 import ATP-binding protein btuD, Vitamin B12-binding protein btuF, ... (8 entities in total)
• Functional Keywords: inner membrane, membrane, transmembrane, transport, atp-binding, hydrolase, nucleotide-binding, periplasm, membrane protein
• Biological source: Escherichia coli; More
• Cellular location: Cell inner membrane; Multi-pass membrane protein: P06609; Cell inner membrane; Peripheral membrane protein: P06611; Periplasm : P37028
• Total number of polymer chains: 5
• Total formula weight: 154599.28

Authors

Hvorup, R.N.,Goetz, B.A.,Niederer, M.,Hollenstein, K.,Perozo, E.,Locher, K.P. (deposition date: 2007-07-03, release date: 2007-08-14, Last modification date: 2024-10-30)

Primary citation

Hvorup, R.N.,Goetz, B.A.,Niederer, M.,Hollenstein, K.,Perozo, E.,Locher, K.P.
Asymmetry in the structure of the ABC transporter-binding protein complex BtuCD-BtuF.
Science, 317:1387-1390, 2007

PubMed Abstract: 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.

PubMed: 17673622
DOI: 10.1126/science.1145950

Experimental method

X-RAY DIFFRACTION (2.6 Å)