1a8y

Publication Abstract from PubMed

Calsequestrin, the major Ca2+ storage protein of muscle, coordinately binds and releases 40-50 Ca2+ ions per molecule for each contraction-relaxation cycle by an uncertain mechanism. We have determined the structure of rabbit skeletal muscle calsequestrin. Three very negative thioredoxin-like domains surround a hydrophilic center. Each monomer makes two extensive dimerization contacts, both of which involve the approach of many negative groups. This structure suggests a mechanism by which calsequestrin may achieve high capacity Ca2+ binding. The suggested mechanism involves Ca2+-induced collapse of the three domains and polymerization of calsequestrin monomers arising from three factors: N-terminal arm exchange, helix-helix contacts and Ca2+ cross bridges. This proposed structure-based mechanism accounts for the observed coupling of high capacity Ca2+ binding with protein precipitation.

Crystal structure of calsequestrin from rabbit skeletal muscle sarcoplasmic reticulum.,Wang S, Trumble WR, Liao H, Wesson CR, Dunker AK, Kang CH Nat Struct Biol. 1998 Jun;5(6):476-83. PMID:9628486^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.