Site-site communication in the EF-hand Ca2+-binding protein calbindin D9k.Maler, L., Blankenship, J., Rance, M., Chazin, W.J.
(2000) Nat Struct Biol 7: 245-250
- PubMed: 10700285
- DOI: https://doi.org/10.1038/73369
- Primary Citation of Related Structures:
- PubMed Abstract:
The cooperative binding of Ca2+ ions is an essential functional property of the EF-hand family of Ca2+-binding proteins. To understand how these proteins function, it is essential to characterize intermediate binding states in addition to the apo- and holo-proteins. The three-dimensional solution structure and fast time scale internal motional dynamics of the backbone have been determined for the half-saturated state of the N56A mutant of calbindin D9k with Ca2+ bound only in the N-terminal site. The extent of conformational reorganization and a loss of flexibility in the C-terminal EF-hand upon binding of an ion in the N-terminal EF-hand provide clear evidence of the importance of site-site interactions in this family of proteins, and demonstrates the strength of long-range effects in the cooperative EF-hand Ca2+-binding domain.
Department of Molecular Biology (MB9), The Scripps Research Institute, 10550 North Torrey Pines Road., La Jolla, California 92037, USA.