Abstract
Calbindin-D28K is a Ca2+-binding protein, performing roles as both a calcium buffer and calcium sensor. The NMR solution structure of Ca2+-loaded calbindin-D28K reveals a single, globular fold consisting of six distinct EF-hand subdomains, which coordinate Ca 2+ in loops on EF1, EF3, EF4 and EF5. Target peptides from Ran-binding protein M and myo-inositol monophosphatase, along with a new target from procaspase-3, are shown to interact with the protein on a surface comprised of α5 (EF3), α8 (EF4) and the EF2-EF3 and EF4-EF5 loops. Fluorescence experiments reveal that calbindin-D28K adopts discrete hydrophobic states as it binds Ca2+. The structure, binding interface and hydrophobic characteristics of Ca2+-loaded calbindin-D 28K provide the first detailed insights into how this essential protein may function. This structure is one of the largest high-resolution NMR structures and the largest monomeric EF-hand protein to be solved to date.
Original language | English (US) |
---|---|
Pages (from-to) | 641-647 |
Number of pages | 7 |
Journal | Nature Structural and Molecular Biology |
Volume | 13 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2006 |
ASJC Scopus subject areas
- Structural Biology
- Molecular Biology