title: How soft is a protein? A protein dynamics force constant measured by neutron scattering.
abstract: An effective environmental force constant is introduced to quantify the molecular resilience (or its opposite, "softness") of a protein structure and relate it to biological function and activity. Specific resilience-function relations were found in neutron-scattering experiments on purple membranes containing bacteriorhodopsin, the light-activated proton pump of halobacteria; the connection between resilience and stability is illustrated by a study of myoglobin in different environments. Important advantages of the neutron method are that it can characterize the dynamics of any type of biological sample-which need not be crystalline or monodisperse-and that it enables researchers to focus on the dynamics of specific parts of a complex structure with deuterium labeling.
authors.affiliation: Institut de Biologie Structurale, 41 rue Jules Horowitz, F-38027 Grenoble Cedex 1, France. zaccai@ibs.fr
authors.forename: G
authors.initials: G
authors.lastname: Zaccai
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000502:physiology; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003903:Deuterium / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry* / Q000502:physiology; D009502:Neutrons; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011522:Protons; D018717:Purple Membrane / Q000737:chemistry; D012542:Scattering, Radiation; D013696:Temperature; D013816:Thermodynamics
chemical_list: D009211:Myoglobin; D011522:Protons; D001436:Bacteriorhodopsins; D003903:Deuterium