Nobel Prize in Chemistry 2013

Transcription

1 Nobel Prize in Chemistry 2013 Kjemi Grand Prix Department of Chemistry University of Oslo October Trygve Helgaker CTCC, Department of Chemistry, University of Oslo

2 The Nobel Prize in Chemistry 2013 for the development of mulescale models for complex chemical systems.

3 MarEn Karplus Harvard University and Université de Strasbourg Born: March , Vienna, Austria CiEzenship: US and Austrian PhD: CalTech, 1953 AffiliaEon: Harvard University, Boston, USA and Université de Strasbourg, Strasbourg, France Field: TheoreEcal Chemistry

4 Michael LeviS Stanford University School of Medicine Born: May , Pretoria, South Africa CiEzenship: US, BriEsh, and Israeli Ph.D.: University of Cambridge 1971 AffiliaEon: Stanford University School of Medicine, Stanford, USA Field: Structural Biology

5 Arieh Warshel University of Southern California Born: November , Kibbutz Sde- Nahum, BriEsh Mandate of PalesEne (now in Israel) CiEzenship: US and Israeli Ph.D.: Weizmann InsEtute, 1969 AffiliaEon: University of Southern California, Los Angeles, USA Field: TheoreEcal Chemistry and biophysics

6 ComputaEon: the third way Theory, experiment and computaeon - interpretaeon and prediceon of experiment - alternaeve to experimental measurements - this is a development seen in all sciences

7 An enormous increase in computer power

8 Development of quantum Chemistry Molecules containing up to a few hundred atoms can nowadays be accurately studied quantum mechanically Such quantum- mechanical calculaeons are expensive but accurate This development was acknowledged with the Nobel Prize in 1998 Walter Kohn for his development of the density-functional theory John Pople for his development of computational methods in quantum chemistry

9 ComputaEon in Chemistry SimulaEons of chemical systems and processes - 40% of all arecles in Journal of American Chemical Society supported by computaeon

10 Molecular Mechanics (MM) Molecules are almost classical but not quite A classical description may be given in terms of empirical classical interatomic forces This classical approach is known as molecular mechanics optimization of structure classical dynamics simulations

11 The birth of computaeonal structural biology The Weizmann InsEtute late 1960s A. Warshel begins PhD study with Shneior Lifson at the Weizmann insetute in 1967 development of the Consistentent Force Field (CFF) program an a`empt to simulate any molecule from a poteneal energy surface (force field) Before his PhD study, M. Levi` is sent to Lifson from Cambridge by John Kendrew in 1967 Kendrew s idea was to apply these methods to proteins and nucleic acid macromolecules Warshel and Levi` complete the CFF code, running it on Golem Warshel applies the code with Lifson to small organic molecules in 1968 Levi` applies the code with Lifson to myoglobin and lysozyme in 1969 Warshel finishes his PhD in 1969 and goes to work with MarEn Karplus at Harvard hybrid methods Levi` completes his PhD ( ) in the Laboratory of Molecular Biology, Cambridge conformaeon analysis of proteins Warshel and Levi` reunite at the Weizmann insetute in 1973 ComputaEonal work on protein folding

12 Lifson and Warshel J. Chem. Phys. 49, 5116 (1968)

13 LeviS and Lifson J. Mol. Biol. 46, 269 (1969)

14 Hybrid methods Karplus and Warshel (1972) goal to study molecules similar to reenal reenal is a polyene chromophore chemical basis for vision only pi electrons treated quantum mechanically (PPP) an empirical poteneal funceon used or the sigma electrons atomizaeon energies, ionizaeon poteneals, equilibrium structures, vibraeonal frequencies, ground and excited states

15 Warshel and Karplus J. Am. Chem. Soc. 94, 5612 (1972)

16 Quantum Mechanics/MolecularMechanics (1976) Warshel and Levi` generalizes the method: QM/MM To understand how lysozyme cleaves a glycoside chain, only the relevant parts need to be studied quantum mechanically

17 Warshel and LeviS J. Mol. Biol. 103, 227 (1976)

18 More general mulescale modeling (1976) Study of protein folding by Levi` and Warshel amino acid residues are assigned interaceon volumes string- of- pearls structure used for simulaeon

19 LeviS and Warshel Nature 253, 694 (1976)

20 Warshel, Nature 260, 679 (1976)

21 Quantum Mechanics/Molecular Mechanics (QM/MM)

22 The Karplus curve The Karplus Curve I Vicinal (three-bond) spin spin coupling constants depend critically on the dihedral angle: I 3 J HH in ethane as a function of the dihedral angle: 14 empirical 12 DFT I Good agreement with the (empirically constructed) Karplus curve Trygve Helgaker (CTCC, University of Oslo) Bonding in magnetic fields ESQC12 62 / 67