title: Collective Excitations in Protein as a Measure of Balance Between its Softness and Rigidity.
abstract: In this article, we elucidate the protein activity from the perspective of protein softness and flexibility by studying the collective phonon-like excitations in a globular protein, human serum albumin (HSA), and taking advantage of the state-of-the-art inelastic X-ray scattering (IXS) technique. Such excitations demonstrate that the protein becomes softer upon thermal denaturation due to disruption of weak noncovalent bonds. On the other hand, no significant change in the local excitations is detected in ligand- (drugs) bound HSA compared to the ligand-free HSA. Our results clearly suggest that the protein conformational flexibility and rigidity are balanced by the native protein structure for biological activity.
authors.affiliation: Department of Physics and Astronomy, Wayne State University , Detroit, MI 48201, United States.
authors.forename: Utsab R
authors.initials: UR
authors.lastname: Shrestha
authors.affiliation: Computational Science and Engineering Division, Oak Ridge National Laboratory , Oak Ridge, TN 37831, United States.
authors.forename: Debsindhu
authors.initials: D
authors.lastname: Bhowmik
authors.affiliation: Department of Physics and Astronomy, Wayne State University , Detroit, MI 48201, United States.
authors.forename: Kurt W
authors.initials: KW
authors.lastname: Van Delinder
authors.affiliation: Chemical and Engineering Materials Division, Oak Ridge National Laboratory , Oak Ridge, TN 37831, United States.
authors.forename: Eugene
authors.initials: E
authors.lastname: Mamontov
authors.affiliation: Biology and Soft Matter Division, Oak Ridge National Laboratory , Oak Ridge, TN 37831, United States.
authors.forename: Hugh
authors.initials: H
authors.lastname: O'Neill
authors.affiliation: Biology and Soft Matter Division, Oak Ridge National Laboratory , Oak Ridge, TN 37831, United States.
authors.forename: Qiu
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Advanced Photon Source, Argonne National laboratory , Argonne, IL 60439, United States.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Alatas
authors.affiliation: Department of Physics and Astronomy, Wayne State University , Detroit, MI 48201, United States.
authors.forename: Xiang-Qiang
authors.identifier: 0000-0003-4320-5316
authors.initials: XQ
authors.lastname: Chu
mesh_terms: D002626:Chemistry, Pharmaceutical; D006801:Humans; D008954:Models, Biological; D004364:Pharmaceutical Preparations / Q000737:chemistry; D011487:Protein Conformation; D011489:Protein Denaturation; D012709:Serum Albumin / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D004364:Pharmaceutical Preparations; D012709:Serum Albumin; D014867:Water