1ujw | pdb_00001ujw
Structure of the complex between BtuB and Colicin E3 Receptor binding domain
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| 1ujw, resolution 2.75Å (default scene) | |||||||||||||
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| Ligands: | AAE, GOL, GP1, LDA, LIM | ||||||||||||
| Related: | 1nqe, 1jch | ||||||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Overview
Cellular import of colicin E3 is initiated by the Escherichia coli outer membrane cobalamin transporter, BtuB. The 135-residue 100-A coiled-coil receptor-binding domain (R135) of colicin E3 forms a 1:1 complex with BtuB whose structure at a resolution of 2.75 A is reported. Binding of R135 to the BtuB extracellular surface (DeltaG(o) = -12 kcal mol(-1)) is mediated by 27 residues of R135 near the coiled-coil apex. Formation of the R135-BtuB complex results in unfolding of R135 N- and C-terminal ends, inferred to be important for unfolding of the colicin T-domain. Small conformational changes occur in the BtuB cork and barrel domains but are insufficient to form a translocation channel. The absence of a channel and the peripheral binding of R135 imply that BtuB serves to bind the colicin, and that the coiled-coil delivers the colicin to a neighboring outer membrane protein for translocation, thus forming a colicin translocon. The translocator was concluded to be OmpF from the occlusion of OmpF channels by colicin E3.
About this Structure
1UJW is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.
Reference
The structure of BtuB with bound colicin E3 R-domain implies a translocon., Kurisu G, Zakharov SD, Zhalnina MV, Bano S, Eroukova VY, Rokitskaya TI, Antonenko YN, Wiener MC, Cramer WA, Nat Struct Biol. 2003 Nov;10(11):948-54. Epub 2003 Oct 5. PMID:14528295 Page seeded by OCA on Sat May 3 11:19:35 2008
