Assembly Kinetics of bc1 Complex Membrane Protein Investigated by Using a Continuous-Angle Laser Light Scattering Technique - Analytical Methods & Tools for Lyophilization

Assembly Kinetics of bc1 Complex Membrane Protein Investigated by Using a Continuous-Angle Laser Light Scattering Technique
Received: April 16, 2003
Web Release Date: September 17, 2003
Kazuo Onuma,* Noriko Kanzaki, and Tomomi Kubota
J. Phys. Chem. B
ACS Publications
Copyright ? 2003 American Chemical Society
Institute for Human Science & Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan, and National Institute of Advanced Industrial Science and Technology, Laboratory of Gene Function Analysis, Institute of Molecular and Cell Biology, Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8566, Japan
Abstract:
The assembly kinetics of a membrane protein, the bc1 complex, was investigated using a newly developed continuous-angle laser light scattering technique. The apparent molecular weight, the radius of gyration, and the fractal dimension of aggregates in the aqueous solutions were calculated by simultaneously measuring the angular dependence on the scattering intensity with a time resolution of 1 s. It was found that the assembly of the bc1 complex proceeded via increases in both the size and packing of the internal structure of the aggregates. This feature was qualitatively the same irrespective of whether zinc was present in the solutions. However, the fractal dimension in the final stage of assembly clearly showed a difference depending on the presence or absence of zinc in the solutions. The observed difference was consistent with the appearance of amorphous or crystalline phases. The assembly rate was controlled by the presence of zinc as well as by the concentration of PEG, the crystallizing reagent. Finally, the observed data were compared to those observed in the aggregation process of inorganic biological molecules, calcium phosphate.
You can view the abstract online. A subscription is required to view the full text or it can be purchased online.