ÿþ<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html lang="fr"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Homepage of Alain Chaumont (Contact)</title> <link rel="stylesheet" type="text/css" href="stylesheet.css"> </head> <body> <div id="global"> <div id="header"> </div> <div id="center"> <div id="content"> <br><br> <h2> Bacteriorhodopsin </h2> <img src="pics/BR_Lstate.jpeg" width="269" height="360" vspace="2" hspace="15" align="left"> <p>Bacteriorhodopsin (BR) is an integral membrane protein in the purple membrane of the Halobacterium salinarum. This protein has the function of a ligth-driven proton pump, establishing actively vectorial proton transport from the cytoplasmic medium to the extracellular side, the resulting H<sup>+</sup> gradient supplying the bacterium with chemical energy to drive ATP synthesis or motor proteins.</p> <p>The photocycle is initiated by the absorption of a photon by the all-trans retinal cofactor, linked to Lys216 via a protonated Schiff base. After the excitation, the retinal isomerizes to a 13-cis state and returns to the electronic ground state within a few thousands femtoseconds during which the protein passes a sequence of photointermediates (K, L, M, ...).</p> <p>During the photocycle distinct sidechains (Asp96, the Schiff base linkage ...) in the transport change their protonation state. The respective protons get promoted to their next intermediate position by hydrogen bond networks of internal water molecules. Although the molecular structure of BR is partially known even on a time-resolved level in terms of the above mentioned intermediates, the detailed microscopic nature of the proton translocation process still remains unclear. </p> <p> The aim of this project is to get valuable informations into the microscopic details underlying the proton translocation process in BR using the recently developped QM / MM coupling scheme introduced by Laio et al. which interfaces the CPMD with the GROMOS molecular mechanics code.</p> <p> For more details on this project please check out the following website: <br> <br> <a href="http://www.theochem.ruhr-uni-bochum.de/research/marx/topic8.en.html">Homepage of the Lehrstuhl f&uuml;r Theoretische Chemie of the University of Bochum</a> </p> </div> <div id="sidebar"> <br><br> <h3><a href="index.html" id="current">Back Home</a></h3> <h3> Research </h3> <div id="navcontainer"> <ul id="navlist"> <li id="active"><a href="AC_IL.html" id="current">Ionic Liquids</a></li> <li><a href="AC_Halide.html">Halide Complexation</a></li> <li><a href="AC_BR.html">Bacteriorhodopsin</a></li> <li><a href="AC_hGBP1.html">hGBP1</a></li> </ul> </div> <h3> Curriculum Vitae </h3> <div id="navcontainer"> <ul id="navlist"> <li id="active"><a href="AC_Career_History.html" id="current">Career History</a></li> <li><a href="AC_Publi.html">Publications</a></li> <li><a href="AC_Posters.html">Posters</a></li> <li><a href="AC_Invited_Talks.html">Invited Talks</a></li> <li><a href="AC_Cover.html">Cover Galery</a></li> <li><a href="AC_Prize.html">Prize Awards</a></li> <li><a href="AC_Contact.html">Contact</a></li> </ul> </div> </div> <div id="footer"> <p>Last Update: 28.03.2007</p> </div> </div> </body> </html>