@article {422,
	title = {Charge Delocalization in Proton Channels, I: the Aquaporin Channels and Proton Blockage},
	journal = {Biophys J},
	volume = {92},
	number = {1},
	year = {2007},
	note = {Chen, Hanning Ilan, Boaz Wu, Yujie Zhu, Fangqiang Schulten, Klaus Voth, Gregory A 2 P41 RR05969/RR/NCRR NIH HHS/United States R01 GM067887/GM/NIGMS NIH HHS/United States R01-GM53148/GM/NIGMS NIH HHS/United States Research Support, N.I.H., Extramural Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S. United States Biophysical journal Biophys J. 2007 Jan 1;92(1):46-60. Epub 2006 Oct 20.},
	pages = {46-60},
	abstract = {<p>The explicit contribution to the free energy barrier and proton conductance from the delocalized nature of the excess proton is examined in aquaporin channels using an accurate all-atom molecular dynamics computer simulation model. In particular, the channel permeation free energy profiles are calculated and compared for both a delocalized (fully Grotthuss shuttling) proton and a classical (nonshuttling) hydronium ion along two aquaporin channels, Aqp1 and GlpF. To elucidate the effects of the bipolar field thought to arise from two alpha-helical macrodipoles on proton blockage, free energy profiles were also calculated for computational mutants of the two channels where the bipolar field was eliminated by artificially discharging the backbone atoms. Comparison of the free energy profiles between the proton and hydronium cases indicates that the magnitude of the free energy barrier and position of the barrier peak for the fully delocalized and shuttling proton are somewhat different from the case of the (localized) classical hydronium. The proton conductance through the two aquaporin channels is also estimated using Poisson-Nernst-Planck theory for both the Grotthuss shuttling excess proton and the classical hydronium cation.</p>},
	keywords = {Aquaporin 1/*chemistry Aquaporins/*chemistry Biological Transport Biophysics/*methods Escherichia coli Proteins/*chemistry Ions Models, Chemical Models, Molecular Models, Secondary Protons Thermodynamics, Statistical Mutation Oxygen/chemistry Protein Structure},
	doi = {10.1529/biophysj.106.091934},
	author = {Chen, H. and B. Ilan and Y. Wu and Zhu, F. and K. Schulten and G. A. Voth}
}
