Parts | Days | Selection | Search | Updates | Downloads | Help

MO: Fachverband Molekülphysik

MO 1: Biomolecules

MO 1.7: Talk

Monday, March 14, 2011, 12:00–12:15, TOE 317

Ab initio calculation of interactions of Ca²⁺, Sr²⁺, Ba²⁺, Cd²⁺, Hg²⁺ and Pb²⁺ with 19 amino acids — •Matti Ropo, Volker Blum, and Matthias Scheffler — Fritz Haber Institut der Max-Planck-Gesellschaft, Berlin, Germany

Ca has a very important role in cellular signaling in all organisms; cytoplasmic concentrations are typically very low, so when present it acts to trigger various signaling. Unfortunately, heavy metals like Pb can potentially disturb Ca dependent functions[1]. In this study, we investigate the interactions of Ca, Sr, Ba, Cd, Pb and Hg ions with 19 different amino acids in vacuo, using accurate ab initio calculations based on density functional theory (DFT) and the van der Waals [2] corrected PBE functional. The conformational search was performed using a force-field based (OPLS-AA) basin hopping search [3], followed by all-electron DFT calculations[4] for a wide range of conformers. For each amino acid, we considered at the outset three different types of termination: uncharged termination (-NH2/-COOH), zwitterionic, and capped with acetyl(ace)/N-Methyl-Amide(nma) groups. The database reveals trends such as: the zwitterionic conformation is preferred over normal almost in all amino acids with Ca ion; the strongest binding energies for Ca are found with ace/nma caps; Ca binds most strongly to arginine; Pb bind uniformly stronger than Ca. [1]H.A. Godwin, Curr.Opin.Chem.Biol. 5, 223 (2001) [2]A. Tkatchenko and M. Scheffler, Phys.Rev.Lett. 102, 73005 (2009) [3]J.W. Ponder,TINKER 5.1; Washington Univ. School of Medicine, Saint Louis, MO (2009) [4]V. Blum et al., Comp.Phys.Comm. 180, 2175 (2009).