COMPACTNESS OF THE KINETIC MOLTEN GLOBULE OF BOVINE ALPHA-LACTALBUMIN- A DYNAMIC LIGHT-SCATTERING STUDY

Citation
K. Gast et al., COMPACTNESS OF THE KINETIC MOLTEN GLOBULE OF BOVINE ALPHA-LACTALBUMIN- A DYNAMIC LIGHT-SCATTERING STUDY, Protein science, 7(9), 1998, pp. 2004-2011
Citations number
37
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biology
Journal title
ISSN journal
0961-8368
Volume
7
Issue
9
Year of publication
1998
Pages
2004 - 2011
Database
ISI
SICI code
0961-8368(1998)7:9<2004:COTKMG>2.0.ZU;2-H
Abstract
During folding of globular proteins, the molten globule state was obse rved as an equilibrium intermediate under mildly denaturing conditions as well as a transient intermediate in kinetic refolding experiments. While the high compactness of the equilibrium intermediate of alpha-l actalbumin has been verified, direct measurements of the compactness o f the kinetic intermediate have not been reported until now. Our dynam ic light scattering measurements provide a complete set of the hydrody namic dimensions of bovine alpha-lactalbumin in different conformation al states, particularly in the kinetic molten globule state. The Stoke s radii for the native, kinetic molten globule, equilibrium molten glo bule, and unfolded states are 1.91, 1.99, 2.08, and 2.36 nm, respectiv ely. Therefore, the kinetic intermediate appears to be even more compa ct than its equilibrium counterpart. Remarkable differences in the con centration dependence of the Stokes radius exist revealing strong attr active but repulsive intermolecular interactions in the kinetic and eq uilibrium molten globule states, respectively. This underlines the imp ortance of extrapolation to zero protein concentration in measurements of the molecular compactness.