Single-Channel Water Permeabilities of Escherichia coli Aquaporins AqpZ and GlpF

@article{citeulike:2735132, abstract = {From equilibrium molecular dynamics simulations we have determined single-channel water permeabilities for Escherichia coli aquaporin Z (AqpZ) and aquaglyceroporin GlpF with the channels embedded in lipid bilayers. GlpF's osmotic water permeability constant pf exceeds by 2-3 times that of AqpZ and the diffusive permeability constant (pd) of GlpF is found to exceed that of AqpZ 2-9-fold. Achieving complete water selectivity in AqpZ consequently implies lower transport rates overall relative to the less selective, wider channel of GlpF. For AqpZ, the ratio pf/pd {cong} 12 is close to the average number of water molecules in the channel lumen, whereas for GlpF, pf/pd {cong} 4. This implies that single-file structure of the luminal water is more pronounced for AqpZ, the narrower channel of the two. Electrostatics profiles across the pore lumens reveal that AqpZ significantly reinforces water-channel interactions, and weaker water-water interactions in turn suppress water-water correlations relative to GlpF. Consequently, suppressed water-water correlations across the narrow selectivity filter become a key structural determinant for water permeation causing luminal water to permeate slower across AqpZ. 10.1529/biophysj.105.073965}, author = {Jensen, Morten O. and Mouritsen, Ole G. }, citeulike-article-id = {2735132}, doi = {10.1529/biophysj.105.073965}, journal = {Biophys. J.}, keywords = {aquaporin}, month = {April}, number = {7}, pages = {2270--2284}, posted-at = {2008-04-29 19:16:11}, priority = {2}, title = {Single-Channel Water Permeabilities of Escherichia coli Aquaporins AqpZ and GlpF}, url = {http://dx.doi.org/10.1529/biophysj.105.073965}, volume = {90}, year = {2006} }

TY - JOUR ID - citeulike:2735132 L3 - citeulike-article-id:2735132 TI - Single-Channel Water Permeabilities of Escherichia coli Aquaporins AqpZ and GlpF JF - Biophys. J. VL - 90 IS - 7 SP - 2270 EP - 2284 N2 - From equilibrium molecular dynamics simulations we have determined single-channel water permeabilities for Escherichia coli aquaporin Z (AqpZ) and aquaglyceroporin GlpF with the channels embedded in lipid bilayers. GlpF's osmotic water permeability constant pf exceeds by 2-3 times that of AqpZ and the diffusive permeability constant (pd) of GlpF is found to exceed that of AqpZ 2-9-fold. Achieving complete water selectivity in AqpZ consequently implies lower transport rates overall relative to the less selective, wider channel of GlpF. For AqpZ, the ratio pf/pd {cong} 12 is close to the average number of water molecules in the channel lumen, whereas for GlpF, pf/pd {cong} 4. This implies that single-file structure of the luminal water is more pronounced for AqpZ, the narrower channel of the two. Electrostatics profiles across the pore lumens reveal that AqpZ significantly reinforces water-channel interactions, and weaker water-water interactions in turn suppress water-water correlations relative to GlpF. Consequently, suppressed water-water correlations across the narrow selectivity filter become a key structural determinant for water permeation causing luminal water to permeate slower across AqpZ. 10.1529/biophysj.105.073965 KW - aquaporin AU - Jensen, Morten AU - Mouritsen, Ole PY - 2006/04/01/ UR - http://dx.doi.org/10.1529/biophysj.105.073965 ER -