Abstract : The development of experimental techniques over the last decades has enabled a finer and finer investigation of the molecular mechanisms underlying biological processes (e.g. photosynthesis, cellular respiration, enzymatic catalysis) up to the point of revealing quantum effects like electron or proton tunneling or long lived coherences. Such fine quantum effects appear as surprising given the warm soft nature of biological media, as opposed to the cold hard world where quantum effects dominate. There is today an intense activity over the world to probe, interpret and understand the relevance of quantum effects in biology. So far, however, it has not been established that quantum effects are required for efficient biological functions. A more detailed understanding of quantum coherent effects demands thorough and comprehensive investigations combining the quantum dynamic theory with structure-based modeling based on quantum chemical calculations and molecular dynamics simulations.

During this presentation I will present some results obtained by our group on the understanding of the role played by coherences in biological electron transfers. I will insist on the current methodological locks and on the computational strategies we are developing to circumvent them. Recent simulations of ultrafast electron transfers within plant cryptochromes will be presented.[3]

Biographie : Aurélien DE LA LANDE Aurélien de la Lande is Chargé de Recherche CNRS, at the Laboratoire de Chimie Physique of University Paris Sud. He graduated from the higher school of Chemistry ESCOM (Ecole Supérieure de Chimie Organique et Minérale) in 2004. He then prepared a PhD in theoretical chemistry under a French-Spanish co-supervision. He investigated the catalytic mechanism of hydroxylation by copper enzymes, employing multi-scale approaches (quantum chemistry, molecular dynamics with classical force fields, hybrid QM/MM schemes). He moved for a two-year post-doctoral position in Calgary, Canada, between 2007 and 2009, to work on the development of Density Functional Theory methods for dealing with electron tunneling in biological systems. His current interests at LCP are centered on the investigation of electron and proton transfers in complex systems such as peptides or proteins. His is particularly interested in the manifestation of electronic coherences biological processes.