title: The influence of solvent composition on global dynamics of human butyrylcholinesterase powders: a neutron-scattering study.
abstract: A major result of incoherent elastic neutron-scattering experiments on protein powders is the strong dependence of the intramolecular dynamics on the sample environment. We performed a series of incoherent elastic neutron-scattering experiments on lyophilized human butyrylcholinesterase (HuBChE) powders under different conditions (solvent composition and hydration degree) in the temperature range from 20 to 285 K to elucidate the effect of the environment on the enzyme atomic mean-square displacements. Comparing D(2)O- with H(2)O-hydrated samples, we were able to investigate protein as well as hydration water molecular dynamics. HuBChE lyophilized from three distinct buffers showed completely different atomic mean-square displacements at temperatures above approximately 200 K: a salt-free sample and a sample containing Tris-HCl showed identical small-amplitude motions. A third sample, containing sodium phosphate, displayed highly reduced mean-square displacements at ambient temperature with respect to the other two samples. Below 200 K, all samples displayed similar mean-square displacements. We draw the conclusion that the reduction of intramolecular protein mean-square displacements on an Angstrom-nanosecond scale by the solvent depends not only on the presence of salt ions but also on their type.
authors.affiliation: Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale, Grenoble, France.
authors.forename: F
authors.initials: F
authors.lastname: Gabel
authors.forename: M
authors.initials: M
authors.lastname: Weik
authors.forename: B P
authors.initials: BP
authors.lastname: Doctor
authors.forename: A
authors.initials: A
authors.lastname: Saxena
authors.forename: D
authors.initials: D
authors.lastname: Fournier
authors.forename: L
authors.initials: L
authors.lastname: Brochier
authors.forename: F
authors.initials: F
authors.lastname: Renault
authors.forename: P
authors.initials: P
authors.lastname: Masson
authors.forename: I
authors.initials: I
authors.lastname: Silman
authors.forename: G
authors.initials: G
authors.lastname: Zaccai
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D002021:Buffers; D002091:Butyrylcholinesterase / Q000737:chemistry*; D017666:Deuterium Oxide; D005612:Freeze Drying; D006801:Humans; D007477:Ions; D015233:Models, Statistical; D009502:Neutrons; D011522:Protons; D012492:Salts / Q000737:chemistry; D012542:Scattering, Radiation; D012997:Solvents; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D002021:Buffers; D007477:Ions; D011522:Protons; D012492:Salts; D012997:Solvents; D014867:Water; D002091:Butyrylcholinesterase; D017666:Deuterium Oxide