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1n2z
From Proteopedia
2.0 Angstrom structure of BtuF, the vitamin B12 binding protein of E. coli
Overview
Bacterial binding protein-dependent ATP binding cassette (ABC) transporters facilitate uptake of essential nutrients. The crystal structure of Escherichia coli BtuF, the protein that binds vitamin B12 and delivers it to the periplasmic surface of the ABC transporter BtuCD, reveals a bi-lobed fold resembling that of the ferrichrome binding protein FhuD. B12 is bound in the "base-on" conformation in a deep cleft formed at the interface between the two lobes of BtuF. A stable complex between BtuF and BtuCD (with the stoichiometry BtuC2D2F) is demonstrated to form in vitro and was modeled using the individual crystal structures. Two surface glutamates from BtuF may interact with arginine residues on the periplasmic surface of the BtuCD transporter. These glutamate and arginine residues are conserved among binding proteins and ABC transporters mediating iron and B12 uptake, suggesting that they may have a role in docking and the transmission of conformational changes.
About this Structure
1N2Z is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
The structure of Escherichia coli BtuF and binding to its cognate ATP binding cassette transporter., Borths EL, Locher KP, Lee AT, Rees DC, Proc Natl Acad Sci U S A. 2002 Dec 24;99(26):16642-7. Epub 2002 Dec 10. PMID:12475936 Page seeded by OCA on Sat May 3 02:01:37 2008
