title: Rigidity, secondary structure, and the universality of the boson peak in proteins.
abstract: Complementary neutron- and light-scattering results on nine proteins and amino acids reveal the role of rigidity and secondary structure in determining the time- and lengthscales of low-frequency collective vibrational dynamics in proteins. These dynamics manifest in a spectral feature, known as the boson peak (BP), which is common to all disordered materials. We demonstrate that BP position scales systematically with structural motifs, reflecting local rigidity: disordered proteins appear softer than α-helical proteins; which are softer than β-sheet proteins. Our analysis also reveals a universal spectral shape of the BP in proteins and amino acid mixtures; superimposable on the shape observed in typical glasses. Uniformity in the underlying physical mechanism, independent of the specific chemical composition, connects the BP vibrations to nanometer-scale heterogeneities, providing an experimental benchmark for coarse-grained simulations, structure/rigidity relationships, and engineering of proteins for novel applications.
authors.affiliation: Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Chemical and Materials Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Department of Chemistry, University of Tennessee, Knoxville, Tennessee.
authors.forename: Stefania
authors.initials: S
authors.lastname: Perticaroli
authors.affiliation: Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Department of Chemistry, University of Tennessee, Knoxville, Tennessee. Electronic address: nickelsjd@ornl.gov.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Nickels
authors.affiliation: Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
authors.forename: Georg
authors.initials: G
authors.lastname: Ehlers
authors.affiliation: Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Chemical and Materials Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Department of Chemistry, University of Tennessee, Knoxville, Tennessee.
authors.forename: Alexei P
authors.initials: AP
authors.lastname: Sokolov
mesh_terms: D000818:Animals; D002417:Cattle; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008958:Models, Molecular; D033363:Neutron Diffraction; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D012542:Scattering, Radiation; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism; D013057:Spectrum Analysis
chemical_list: D011506:Proteins; D049452:Green Fluorescent Proteins; D012710:Serum Albumin, Bovine