Zn2+ binding to cardiac calsequestrin.
Zn2+ binding to canine cardiac calsequestrin was investigated using the Zn2+ specific fluorescence dye salicylcarbohydrazone (SACH), 65Zn2+ overlay and Zn(2+)-IDA chromatography. Cardiac calsequestrin binds approximately 200 moles of Zn2+/mole of protein with the Kd = 300 microM. Zn2+ binding to calsequestrin was further confirmed by 65Zn2+ overlay and Zn(2+)-dependent aggregation of the protein. However, calsequestrin did not bind to a Zn(2+)-IDA-agarose column, indicating that histidine residues may not be involved in Zn2+ binding to the protein. Circular dichroism revealed only minor Zn(2+)-dependent conformational changes in calsequestrin. We conclude that calsequestrin is a Ca(2+)- and Zn(2+)-binding protein and that Zn2+ may modulate the structure and function of the protein.
Baksh
S
S
Department of Pediatrics, University of Alberta, Edmonton, Canada.
Spamer
C
C
Oikawa
K
K
McCubbin
W D
WD
Heilmann
C
C
Kay
C M
CM
Michalak
M
M
D000818:Animals; D002155:Calsequestrin / Q000737:chemistry / Q000378:metabolism*; D002846:Chromatography, Affinity; D002942:Circular Dichroism; D004285:Dogs; D005456:Fluorescent Dyes; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D051381:Rats; D013056:Spectrophotometry, Ultraviolet; D015032:Zinc / Q000378:metabolism*
D002155:Calsequestrin; D005456:Fluorescent Dyes; D015032:Zinc