Association and dissociation of the calcium-binding domains of calpain by Ca2+.
The calmodulin-like domain of calpain is important for the association of the calpain large and small subunits. We expressed the calmodulin-like domains of the large subunits of rabbit mu- and m-calpains and their small subunits in E. coli and purified them to homogeneity. Unlike the full-length subunits, the calmodulin-like domains are soluble in buffer containing Ca2+. We performed gel filtration chromatography of the purified proteins and found that all three calmodulin-like domains exist as homodimers in the absence of Ca2+ and dissociate into monomers upon the addition of Ca2+.
Suo
S
S
Institute of Molecular and Cellular Bioscience, University of Tokyo, Tokyo, 113-0032, Japan.
Koike
H
H
Sorimachi
H
H
Ishiura
S
S
Suzuki
K
K
D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism; D002154:Calpain / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002850:Chromatography, Gel; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008970:Molecular Weight; D017830:Octoxynol; D010446:Peptide Fragments / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D011489:Protein Denaturation; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012995:Solubility; D014508:Urea / Q000494:pharmacology
D002147:Calmodulin; D007527:Isoenzymes; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D014508:Urea; D017830:Octoxynol; D002154:Calpain; D002118:Calcium