Download MendeleyStructure of the Monomeric Outer-Membrane Porin Ompg in the Open and Closed Conformation.
Yildiz, O., Vinothkumar, K.R., Goswami, P., Kuhlbrandt, W.(2006) EMBO J 25: 3702
- PubMed: 16888630
- DOI: https://doi.org/10.1038/sj.emboj.7601237
- Primary Citation of Related Structures:
2IWV, 2IWW - PubMed 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 beta-barrel, with short periplasmic turns and seven extracellular loops. Crystals grown at neutral pH show the channel in the open state at 2.3 A resolution. In the 2.7 A 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 A 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 A structure, OmpG binds one OG and one glucose molecule as sugar substrates in the closed pore.
Organizational Affiliation:
Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
