title: Picosecond dynamics in haemoglobin from different species: a quasielastic neutron scattering study.
abstract: BACKGROUND
  Dynamics in haemoglobin from platypus (Ornithorhynchus anatinus), chicken (Gallus gallus domesticus) and saltwater crocodile (Crocodylus porosus) were measured to investigate response of conformational motions on the picosecond time scale to naturally occurring variations in the amino acid sequence of structurally identical proteins.
  
  
  METHODS
  Protein dynamics was measured using incoherent quasielastic neutron scattering. The quasielastic broadening was interpreted first with a simple single Lorentzian approach and then by using the Kneller-Volino Brownian dynamics model.
  
  
  RESULTS
  Mean square displacements of conformational motions, diffusion coefficients of internal dynamics and residence times for jump-diffusion between sites and corresponding effective force constants (resilience) and activation energies were determined from the data.
  
  
  CONCLUSIONS
  Modifications of the physicochemical properties caused by mutations of the amino acids were found to have a significant impact on protein dynamics. Activation energies of local side chain dynamics were found to be similar between the different proteins being close to the energy, which is required for the rupture of single hydrogen bond in a protein.
  
  
  CONCLUSIONS
  The measured dynamic quantities showed significant and systematic variations between the investigated species, suggesting that they are the signature of an evolutionary adaptation process stimulated by the different physiological environments of the respective protein.
authors: Jülich Centre for Neutron Science (JCNS) and Institute of Complex Systems (ICS), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany. Electronic address: a.stadler@fz-juelich.de.
authors: Andreas M
authors: AM
authors: Stadler
authors: Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia.
authors: Christopher J
authors: CJ
authors: Garvey
authors: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
authors: Jan Peter
authors: JP
authors: Embs
authors: Institut Laue-Langevin, CS 20156, 38042 Grenoble, France.
authors: Michael Marek
authors: MM
authors: Koza
authors: Technische Universität München, Physik Department E13 and Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), Garching bei München, Germany; Friedrich-Alexander-Universität Erlangen-Nürnberg, Physik Department, Lehrstuhl für Kristallographie und Strukturphysik, Erlangen, Germany.
authors: Tobias
authors: T
authors: Unruh
authors: FH Aachen, Institute for Bioengineering, Heinrich-Mußmann-Straße 1, 52428 Jülich, Germany.
authors: Gerhard
authors: G
authors: Artmann
authors: Institut Laue-Langevin and CNRS, CS 20156, 38042 Grenoble, France.
authors: Giuseppe
authors: G
authors: Zaccai
mesh_terms: D000489:Alligators and Crocodiles; D000818:Animals; D002645:Chickens; D006454:Hemoglobins / Q000737:chemistry*; D033363:Neutron Diffraction; D010987:Platypus; D053838:Scattering, Small Angle; D013045:Species Specificity
chemical_list: D006454:Hemoglobins
keywords: Body temperature adaptation; Haemoglobin; Picosecond dynamics; Protein dynamics; Quasielastic neutron scattering