Spontaneous Formation of Detergent Micelles around the Outer Membrane Protein OmpX Export

@article{citeulike:2279185, abstract = {The structure and flexibility of the outer membrane protein X (OmpX) in a water-detergent solution and in pure water are investigated by molecular dynamics simulations on the 100-ns timescale and compared with NMR data. The simulations allow for an unbiased determination of the structure of detergent micelles and the protein-detergent mixed micelle. The short-chain lipid dihexanoylphosphatidylcholine, as a detergent, aggregates into pure micelles of [\~{}]18 molecules, or alternatively, it binds to the protein surface. The detergent binds in the form of a monolayer ring around the hydrophobic {beta}-barrel of OmpX rather than in a micellar-like oblate; [\~{}]40 dihexanoylphosphatidylcholine lipids are sufficient for an effective suppression of water from the surface of the {beta}-barrel region. The phospholipids bind also on the extracellular, protruding {beta}-sheet. Here, polar interactions between charged amino acids and phosphatidylcholine headgroups act as condensation seed for detergent micelle formation. The polar protein surface remains accessible to water molecules. In total, [\~{}]90-100 detergent molecules associate within the protein-detergent mixed micelle, in agreement with experimental estimates. The simulation results indicate that OmpX is not a water pore and support the proposed role of the protruding {beta}-sheet as a "fishing rod". 10.1529/biophysj.105.060426}, author = {Bockmann, Rainer A. and Caflisch, Amedeo}, citeulike-article-id = {2279185}, citeulike-linkout-0 = {http://dx.doi.org/10.1529/biophysj.105.060426}, citeulike-linkout-1 = {http://www.biophysj.org/cgi/content/abstract/88/5/3191}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/15749771}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=15749771}, day = {1}, doi = {10.1529/biophysj.105.060426}, journal = {Biophys. J.}, keywords = {barrel, beta, detergent, membrane, micelles, protein}, month = {May}, number = {5}, pages = {3191--3204}, posted-at = {2008-09-01 04:35:49}, priority = {3}, title = {Spontaneous Formation of Detergent Micelles around the Outer Membrane Protein OmpX}, url = {http://dx.doi.org/10.1529/biophysj.105.060426}, volume = {88}, year = {2005} }

TY - JOUR ID - citeulike:2279185 L3 - citeulike-article-id:2279185 N2 - The structure and flexibility of the outer membrane protein X (OmpX) in a water-detergent solution and in pure water are investigated by molecular dynamics simulations on the 100-ns timescale and compared with NMR data. The simulations allow for an unbiased determination of the structure of detergent micelles and the protein-detergent mixed micelle. The short-chain lipid dihexanoylphosphatidylcholine, as a detergent, aggregates into pure micelles of [~]18 molecules, or alternatively, it binds to the protein surface. The detergent binds in the form of a monolayer ring around the hydrophobic {beta}-barrel of OmpX rather than in a micellar-like oblate; [~]40 dihexanoylphosphatidylcholine lipids are sufficient for an effective suppression of water from the surface of the {beta}-barrel region. The phospholipids bind also on the extracellular, protruding {beta}-sheet. Here, polar interactions between charged amino acids and phosphatidylcholine headgroups act as condensation seed for detergent micelle formation. The polar protein surface remains accessible to water molecules. In total, [~]90-100 detergent molecules associate within the protein-detergent mixed micelle, in agreement with experimental estimates. The simulation results indicate that OmpX is not a water pore and support the proposed role of the protruding {beta}-sheet as a "fishing rod". 10.1529/biophysj.105.060426 IS - 5 JF - Biophys. J. EP - 3204 TI - Spontaneous Formation of Detergent Micelles around the Outer Membrane Protein OmpX VL - 88 SP - 3191 KW - barrel KW - beta KW - detergent KW - membrane KW - micelles KW - protein AU - Bockmann, Rainer AU - Caflisch, Amedeo PY - 2005/05/01/ UR - http://dx.doi.org/10.1529/biophysj.105.060426 ER -