The effects of Ca2+ binding on the conformation of calbindin D-28K A nuclear magnetic resonance and microelectrospray mass spectrometry study
Calbindin D-28K is a six-EF-hand calcium-binding protein found in the brain, peripheral nervous system, kidney, and intestine. There is a paucity of information on the effects of calcium binding on calbindin D-28K structure. To further examine the mechanism and structural consequences of calcium binding to calbindin D-28K we performed detailed complementary heteronuclear NMR and microelectrospray mass spectrometry investigations of the calcium-induced conformational changes of calbindin D-28K. The combined use of these two powerful analytical techniques clearly and very rapidly demonstrates the following: (i) apo-calbindin D-28K has an ordered structure which changes to a notably different ordered conformation upon Ca2+ loading, (ii) calcium binding is a sequential process and not a simultaneous event, and (iii) EF-hands 1, 3, 4, and 5 take up Ca2+, whereas EF-hands 2 and 6 do not. Our results support the opinion that calbindin D-28K has characteristics of both a calcium sensor and a buffer. (C) 2003 Elsevier Science (USA). All rights reserved.
Venters, R. A., Benson, L. M., Craig, T. A., Paul, K. H., Kordys, D. R., Thompson, R., ... Cavanagh, J. (2003). The effects of Ca2+ binding on the conformation of calbindin D-28K: A nuclear magnetic resonance and microelectrospray mass spectrometry study. Analytical Biochemistry, 317(1), 59-66. DOI: 10.1016/S0003-2697(03)00084-8