Picosecond dynamics in haemoglobin from different species: A quasielastic neutron scattering study

• Published in: Biochimica et biophysica acta Vol. 1840; no. 10; pp. 2989 - 2999
• Main Authors: Stadler, Andreas M., Garvey, Christopher J., Embs, Jan Peter, Koza, Michael Marek, Unruh, Tobias, Artmann, Gerhard, Zaccai, Giuseppe
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2014; Elsevier
• Subjects: activation energy; Alligators and Crocodiles; amino acid sequences; amino acids; Animals; Biochemistry, Molecular Biology; Body temperature adaptation; Chickens; Crocodylus porosus; diffusivity; energy; evolutionary adaptation; Gallus gallus; Haemoglobin; hemoglobin; Hemoglobins - chemistry; hydrogen bonding; Life Sciences; molecular dynamics; mutation; Neutron Diffraction; Ornithorhynchus anatinus; Picosecond dynamics; Platypus; Protein dynamics; Quasielastic neutron scattering; Scattering, Small Angle; Species Specificity; Structural Biology; Body temperature adaptation; Haemoglobin; Picosecond dynamics; Protein dynamics; Quasielastic neutron scattering
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2014.06.007

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. 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. 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. 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. 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. [Display omitted] •Dynamics of haemoglobin (Hb) from different species studied using neutron scattering•Naturally occurring mutations of the amino acids have impact on protein dynamics.•Softening of Hb close to body temperature of endotherms but not in exotherms•Activation energies are in the order of a single hydrogen bond.•Differences in the dynamics might be signature of an evolutionary adaptation process.