|
 |
|
|
| Subject Categories: Microbiology & Pathogens | Structural Biology |
|
| The EMBO Journal
(2006) 25, 3702–3713, doi:10.1038/sj.emboj.7601237 Published online 3 August 2006 |
|
| Structure of the monomeric outer-membrane porin OmpG in the open and closed conformation |
|
|
| Özkan Yildiz, Kutti R Vinothkumar1, Panchali Goswami and Werner Kühlbrandt |
|
|
Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany To whom correspondence should be addressed Werner Kühlbrandt, Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, Frankfurt am Main 60438, Germany. Tel.: +49 69 6303 3000; Fax: +49 69 6303 3002; E-mail: werner.kuehlbrandt@mpibp-frankfurt.mpg.de 1 Present address: Structural Studies Division, Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK Received 28 April 2006; Accepted 14 June 2006; Published online 3 August 2006. |
|
|
|
| Abstract |
|
OmpG, a monomeric pore-forming protein from Escherichia coli outer membranes, was refolded from inclusion bodies and crystallized in two different conformations. The OmpG channel is a 14-stranded  -barrel, with short periplasmic turns and seven extracellular loops. Crystals grown at neutral pH show the channel in the open state at 2.3 Å resolution. In the 2.7 Å structure of crystals grown at pH 5.6, the pore is blocked by loop 6, which folds across the channel. The rearrangement of loop 6 appears to be triggered by a pair of histidine residues, which repel one another at acidic pH, resulting in the breakage of neighbouring H-bonds and a lengthening of loop 6 from 10 to 17 residues. A total of 151 ordered LDAO detergent molecules were found in the 2.3 Å structure, mostly on the hydrophobic outer surface of OmpG, mimicking the outer membrane lipid bilayer, with three LDAO molecules in the open pore. In the 2.7 Å structure, OmpG binds one OG and one glucose molecule as sugar substrates in the closed pore. |
|
| Keywords: 2D crystallization, membrane protein, protein function, X-ray crystallography |
|
| |
| |
| |
 | Email link to a friend |
| |
 | Download PDF |
| |
 | Full text |
| |
| |
| |
 | Next article |
| |
 | Previous article |
| |
 | Table of contents |
| |
| |
 | Rights and permissions |
| |
 | Reprints |
| |
| |
| |
 Register for table of contents by email | |
| |
| |
| |
