The Laboratoire International Associé between the Centre National de la Recherche Scientifique and the University of Illinois at Urbana-Champaign was launched at the end of 2012. Its primary objective is to develop methods for high-performance molecular simulation with the aim of understanding the function of complex biological assemblies, transcending the frontiers of traditional disciplines by uniting mathematicians, physicists, theoretical chemists and biologists on both sides of the Atlantic. In France, the major contributors are located at the Université de Lorraine, the École des Ponts ParisTech, the Institut de Biologie Structurale and the Laboratoire de Biologie Physico-Chimique. In the United States, the contributors belong to the NIH Resource for Macromolecular Modeling and Bioinformatics. In Nancy, the partner is a theoretical chemistry and biophysics group incepted in 2003. Its expertise lies in describing the structure and the dynamic properties of the biological membrane and elucidating the mechanisms of the cell machinery. To attain this goal, its members leverage numerical simulations over size and timescales commensurate with the biological process at hand. Over the years, the team has gleaned milestone results in such diverse research areas as membrane transport, interaction with the biological membrane, membrane protein structure and function, as well as self-organized molecular systems. They also develop original approaches in the field of free-energy calculations to tackle rare events in biology.
Highlight
Committor-Consistent Variational String Method. The treatment of slow and rare transitions in the simulation of complex systems poses a great computational challenge. A powerful approach to tackle this challenge is the string method, which represents the transition path as a one-dimensional curve in a multidimensional space of collective variables. Commonly used strategies for pathway optimization include aligning the tangent of the string to the local mean force or to the mean drift determined from swarms of short trajectories. Here, a novel strategy is proposed, allowing the string to be optimized based on a variational principle involving the unidirectional reactive flux expressed in terms of the time-correlation function of the committor. The method is illustrated with model systems and then probed with the alanine dipeptide and a coarse-grained model of the barstar-barnase protein complex. Successive iterations variationally refine the string toward an optimal transition pathway following the gradient of the committor between two metastable states. Journal of Physical Chemistry Letters, 2022.
Recent publications
Free Energy Methods for the Description of Molecular Processes
Christophe Chipot;
Annual Review of Biophysics (2023) 52 (1):
A Practical Guide to Recent Advances in Multiscale Modeling and Simulation of BiomoleculesEnhanced Sampling Based on Collective Variables
Yong Wang; Ruhong Zhou; Haohao Fu; Wensheng Cai; Christophe Chipot; Xueguang Shao; (2023) 1-22
Chasing collective variables using temporal data-driven strategies
Haochuan Chen; Christophe Chipot;
QRB Discovery (2023) 413 (242-
