The influence of solvent composition on global dynamics of human butyrylcholinesterase powders: a neutron-scattering study.
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.
Gabel
F
F
Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale, Grenoble, France.
Weik
M
M
Doctor
B P
BP
Saxena
A
A
Fournier
D
D
Brochier
L
L
Renault
F
F
Masson
P
P
Silman
I
I
Zaccai
G
G
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
D002021:Buffers; D007477:Ions; D011522:Protons; D012492:Salts; D012997:Solvents; D014867:Water; D002091:Butyrylcholinesterase; D017666:Deuterium Oxide