title: Protein elasticity probed with two synchrotron-based techniques.
abstract: Compressibility characterizes three interconnecting properties of a protein: dynamics, structure, and function. The compressibility values for the electron-carrying protein cytochrome c and for other proteins, as well, available in the literature vary considerably. Here, we apply two synchrotron-based techniques--nuclear resonance vibrational spectroscopy and inelastic x-ray scattering--to measure the adiabatic compressibility of this protein. This is the first report of the compressibility of any material measured with this method. Unlike the methods previously used, this novel approach probes the protein globally, at ambient pressure, does not require the separation of protein and solvent contributions to the total compressibility, and uses samples that contain the heme iron, as in the native state. We show, by comparing our results with molecular dynamics predictions, that the compressibility is almost independent of temperature. We discuss potential applications of this method to other materials beyond proteins.
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439, USA. leu@aps.anl.gov
authors.forename: Bogdan M
authors.initials: BM
authors.lastname: Leu
authors.forename: Ahmet
authors.initials: A
authors.lastname: Alatas
authors.forename: Harald
authors.initials: H
authors.lastname: Sinn
authors.forename: E Ercan
authors.initials: EE
authors.lastname: Alp
authors.forename: Ayman H
authors.initials: AH
authors.lastname: Said
authors.forename: Hasan
authors.initials: H
authors.lastname: Yavaş
authors.forename: Jiyong
authors.initials: J
authors.lastname: Zhao
authors.forename: J Timothy
authors.initials: JT
authors.lastname: Sage
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Sturhahn
mesh_terms: D000818:Animals; D003574:Cytochrome c Group / Q000737:chemistry*; D004548:Elasticity; D006736:Horses; D012542:Scattering, Radiation; D013057:Spectrum Analysis; D014965:X-Rays
chemical_list: D003574:Cytochrome c Group