<?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%">Roselli, Cecile</style></author><author><style face="normal" font="default" size="100%">Boussac, A</style></author><author><style face="normal" font="default" size="100%">Mattioli, T A</style></author><author><style face="normal" font="default" size="100%">Griffiths, Jennifer A.</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%">Detection of a Yb3+ binding site in regenerated bacteriorhodopsin that is coordinated with the protein and phospholipid head groups.</style></title><secondary-title><style face="normal" font="default" size="100%">Proceedings of the National Academy of Sciences of the United States of America</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Proc. Natl. Acad. Sci. U.S.A.</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%">Metals, Rare Earth</style></keyword><keyword><style  face="normal" font="default" size="100%">Phospholipids</style></keyword><keyword><style  face="normal" font="default" size="100%">Retinaldehyde</style></keyword><keyword><style  face="normal" font="default" size="100%">Spectroscopy, Near-Infrared</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1996 Dec 10</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">93</style></volume><pages><style face="normal" font="default" size="100%">14333-7</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Near infrared Yb3+ vibronic sideband spectroscopy was used to characterize specific lanthanide binding sites in bacteriorhodopsin (bR) and retinal free bacteriorhodopsin (bO). The VSB spectra for deionized bO regenerated with a ratio of 1:1 and 2:1 ion to bO are identical. Application of a two-dimensional anti-correlation technique suggests that only a single Yb3+ site is observed. The Yb3+ binding site in bO is observed to consist of PO2- groups and carboxylic acid groups, both of which are bound in a bidentate manner. An additional contribution most likely arising from a phenolic group is also observed. This implies that the ligands for the observed single binding site are the lipid head groups and amino acid residues. The vibronic sidebands of Yb3+ in deionized bR regenerated at a ratio of 2:1 ion to bR are essentially identical to those in bO. The other high-affinity binding site is thus either not evident or its fluorescence is quenched. A discussion is given on the difference in binding of Ca2+ (or Mg2+) and lanthanides in phospholipid membrane proteins.</style></abstract><issue><style face="normal" font="default" size="100%">25</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/8962051?dopt=Abstract</style></custom1></record></records></xml>