Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 9: Biomaterials and Biopolymers I (joint BP/CPP)
BP 9.1: Talk
Monday, March 16, 2015, 14:30–14:45, EB 202
Determination of Conformational Entropy of Fully and Partially Folded Conformations of Holo- and Apomyoglobin — •Andreas Stadler1, Marek Koza2, and Jörg Fitter3,4 — 1Jülich Centre for Neutron Science JCNS and Institute for Complex Systems ICS, Forschungszentrum Jülich GmbH, 52425 Jülich — 2Institut Laue-Langevin, CS 20156, 38042 Grenoble, France — 3Institute of Complex Systems (ICS-5): Molecular Biophysics, Forschungszentrum Jülich GmbH, 52425 Jülich — 4I. Physikalisches Institut (IA), AG Biophysik, RWTH Aachen, Sommerfeldstrasse 14, 52074 Aachen
Holo- and apomyoglobin can be stabilized in native folded, partially folded molten globules (MGs) and denatured states depending on the solvent composition. In a comparative experimental study we investigated the correlation between protein folding and dynamics on the picosecond time scale using incoherent quasielastic neutron scattering (QENS). The conformational entropy difference ΔSconf between the folded conformations and the acid denatured state could be determined from the measured mean square displacements and was compared to the entropy difference ΔS obtained from thermodynamic parameters. The observed difference between ΔS and ΔSconf was attributed to the entropy difference ΔShydr of dynamically disordered water molecules of the hydration shell. The entropy content of the hydration water is significantly larger in the native folded proteins than in the partially folded MGs. We demonstrate the potential of incoherent neutron scattering for the investigation of the role of conformational dynamics in protein folding.