BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Biology from First Principles? - Professor Mike Payne\, Cavendish Laboratory DTSTART:20060623T083000Z DTEND:20060623T091500Z UID:TALK5083@talks.cam.ac.uk CONTACT:Duncan Simpson DESCRIPTION:One of the challenges confronting biology is to move from a qu alitative understanding of biological systems to a quantitative understand ing. The Genome Project has\, in principle\, provided us with all the inpu t information necessary to model biological systems. Systems Biology is ad dressing the question of how resilient yet adaptive systems\, characterist ic of living cells and organisms\, arise from the complex web of interacti ons between the component parts. The relationship between the Genome and S ystem Biology is extraordinarily complex but this relationship is ultimate ly determined by the atomistic scale behaviour of the components of the bi ological system. In this respect\, biology is no different from many syste ms in the physical sciences where the behaviour of systems is ultimately d etermined by the processes that occur at the atomic scale. It is now known \, from extensive experience in these physical sciences\, that the behavio ur at the atomistic scale can be accurately predicted using parameter free quantum mechanical calculations based on density functional theory. These calculations are often referred to as first principles or ab initio. For instance\, such first principles calculations have provided an understandi ng of the molten core of the earth [1]\, of chemical reactions in numerous different environments [for examples see 2\,3]\, of the growth of oxide f ilms on aluminium [4] and silicon [5] surfaces and there many thousands of other applications. These applications provide a glimpse of the potential impact of quantum mechanical modelling in biology. For instance\, our sim ulations of the reaction of methanol in zeolites [3] showed that\, despite decades of research\, none of the existing models of the behaviour of thi s system was correct. This begs the question If we are unable to correctly predict the behaviour of a few tens of atoms in a very well defined confi guration what is the chance that we can genuinely predict the atomic scale behaviour of biological systems? While motivating a need for first princi ples simulations in biology\, the system sizes and timescales needed to st udy biological problems make the application of first principles technique s extraordinarily challenging.\n In this talk I shall first outline some s uccessful applications of first principles calculations to biological prob lems. I shall then describe two computational techniques we are currently developing that\, we hope\, will make first principles calculations on bio logical systems accessible to all researchers. The first of these techniqu es is ONETEP\, a density functional theory code whose computational cost s cales linearly with the number of atoms in the system. ONETEP allows first principles calculations to be routinely performed on systems containing m any thousands of atoms. The second of these techniques is a hybrid or QM/M M modelling scheme which we are developing in collaboration with Dr. De Vi ta of Kings College\, London. What makes our hybrid scheme special is that the choice of which atoms should be treated quantum mechanically can be d elegated to the computer and is allowed to vary during the simulation.\n\n References\n[1] D. Alfe\, M.J. Gillan and G.D. Price\, Nature 401\, 462 (1 999).\n\n[2] A. De Vita\, I. Stich\, M.J. Gillan\, M.C. Payne and L.J. Clarke\, Phys.Rev.Lett. 71 1276 (1993).\n\n[3] I. Stich\, J.D. Gale K. Te rakura and M.C. Payne\, Chem.Phys.Lett. 283\, 402 (1998) \n\n[4] L.C. Ciac chi and M.C. Payne\, Phys.Rev.Lett 92\, 176104 (2004).\n\n[5] L.C. Ciacch i and M.C. Payne\, Phys.Rev.Lett 95\, 196101 (2005). LOCATION:Emmanuel College Cambridge END:VEVENT END:VCALENDAR