This Article Figures Only Full Text Full Text (PDF) Supporting Appendix Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a colleague Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Copyright Permission Citing Articles Citing Articles via CrossRef Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Coto, P. B. Articles by Olivucci, M. Search for Related Content PubMed PubMed Citation Articles by Coto, P. B. Articles by Olivucci, M. Pubmed/NCBI databases Substance via MeSH Social Bookmarking                What's this?

 Previous Article  | Table of Contents |  Next Article 

PHYSICAL SCIENCES / BIOLOGICAL SCIENCES / CHEMISTRY / BIOPHYSICS
The color of rhodopsins at the ab initio multiconfigurational perturbation theory resolution

Pedro B. Coto, Angela Strambi, Nicolas Ferré, and Massimo Olivucci^,,¶

Dipartimento di Chimica, Università di Siena, via Aldo Moro 2, I-53100 Siena, Italy; Laboratoire de Chimie Théorique et de Modélisation Moléculaire, Unite Mixte de Recherche 6517, Centre National de la Recherche Scientifique, Université de Provence, Case 521 Faculté de Saint-Jérôme, Avenue Esc. Normandie Niemen, 13397 Marseille Cedex 20, France; and Chemistry Department, Bowling Green State University, Bowling Green, OH 43403

Edited by Ernest R. Davidson, University of Washington, Seattle, WA, and approved September 18, 2006 (received for review May 17, 2006)

We demonstrate that "brute force" quantum-mechanics/molecular-mechanics computations based on ab initio (i.e., first principles) multiconfigurational perturbation theory can reproduce the absorption maxima of a set of modified bovine rhodopsins with an accuracy allowing for the analysis of the factors determining their colors. In particular, we show that the theory accounts for the changes in excitation energy even when the proteins display the same charge distribution. Three color-tuning mechanisms, leading to changes of close magnitude, are demonstrated to operate in these conditions. The first is based on the change of the conformation of the conjugated backbone of the retinal chromophore. The second operates through the control of the distance between the positive charge residing on the chromophore and the carboxylate counterion. Finally, the third mechanism operates through the changes in orientation of the chromophore relative to the protein. These results offer perspectives for the unbiased computational design of mutants or chemically modified proteins with wanted optical properties.

excited states | quantum mechanics/molecular mechanics

The authors declare no conflict of interest.

This article is a PNAS direct submission.

^¶To whom correspondence should be addressed. E-mail: olivucci{at}unisi.it or molivuc{at}bgnet.bgsu.edu

© 2006 by The National Academy of Sciences of the USA

CiteULike    Complore    Connotea    Del.icio.us    Digg    What's this?

Current Issue | Archives | Online Submission | Info for Authors | Editorial Board | About Subscribe | Advertise | Contact | Site Map Copyright © 2006 by the National Academy of Sciences