<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Yang, Difei</style></author><author><style face="normal" font="default" size="100%">El-Sayed, Mostafa A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The Ca2+ binding to deionized monomerized and to retinal removed bacteriorhodopsin.</style></title><secondary-title><style face="normal" font="default" size="100%">Biophysical journal</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biophys. J.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacteriorhodopsins</style></keyword><keyword><style  face="normal" font="default" size="100%">Binding Sites</style></keyword><keyword><style  face="normal" font="default" size="100%">Biophysical Phenomena</style></keyword><keyword><style  face="normal" font="default" size="100%">Biophysics</style></keyword><keyword><style  face="normal" font="default" size="100%">Calcium</style></keyword><keyword><style  face="normal" font="default" size="100%">Electrochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Halobacterium</style></keyword><keyword><style  face="normal" font="default" size="100%">Ions</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Protein Conformation</style></keyword><keyword><style  face="normal" font="default" size="100%">Retinaldehyde</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1995</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1995 Nov</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">69</style></volume><pages><style face="normal" font="default" size="100%">2056-9</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In our continuing effort to characterize the metal cation binding in bacteriorhodopsin (bR) using Ca(2+)-specific electrodes, potentiometric titration was carried out on deionized solubilized bR (containing monomeric units) and deionized bacterioopsin (bR with its retinal removed). Scatchard plots were analyzed. The monomer was found to have plots similar to those of the trimer, suggesting that the binding sites in bR are localized within the protein monomer unit and not between the molecules within the trimer structure. This also supports the previous assumption that the curvature in the Scatchard plot of regenerated bR is not due to cooperativity of metal cation within the trimer, but rather due to multiple sites. Recent studies further support the finding that the curved Scatchard plot is not due to the cooperativity between the metal ions in the two high affinity sites, wherever they are. The results of the analysis of the Scatchard plot for deionized bacterioopsin have shown a change in the binding characteristics of the high affinity but not the low affinity sites from that observed in bR. This result supports previous conclusions that metal cations in the high affinity sites are not far from the retinal cavity.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/8580348?dopt=Abstract</style></custom1><electronic-resource-num><style face="normal" font="default" size="100%">10.1016/S0006-3495(95)80075-5</style></electronic-resource-num></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Song, Li</style></author><author><style face="normal" font="default" size="100%">Logunov, Stephan L.</style></author><author><style face="normal" font="default" size="100%">Yang, Difei</style></author><author><style face="normal" font="default" size="100%">El-Sayed, Mostafa A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The pH dependence of the subpicosecond retinal photoisomerization process in bacteriorhodopsin: evidence for parallel photocycles.</style></title><secondary-title><style face="normal" font="default" size="100%">Biophysical journal</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Biophys. J.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Bacteriorhodopsins</style></keyword><keyword><style  face="normal" font="default" size="100%">Biophysical Phenomena</style></keyword><keyword><style  face="normal" font="default" size="100%">Biophysics</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrogen-Ion Concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Isomerism</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Molecular Structure</style></keyword><keyword><style  face="normal" font="default" size="100%">Photochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Retinaldehyde</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1994</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1994 Nov</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">67</style></volume><pages><style face="normal" font="default" size="100%">2008-12</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The pH dependence of the subpicosecond decay of the retinal photoexcited state in bacteriorhodopsin (bR) is determined in the pH range 6.8-11.3. A rapid change in the decay rate of the retinal photoexcited state is observed in the pH range 9-10, the same pH range in which a rapid change in the M412 formation kinetics was observed. This observation supports the previously proposed heterogeneity model in which parallel photocycles contribute to the observed pH dependence of the M412 formation kinetics in bR.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/7858138?dopt=Abstract</style></custom1><electronic-resource-num><style face="normal" font="default" size="100%">10.1016/S0006-3495(94)80684-8</style></electronic-resource-num></record></records></xml>