Studies on the interaction of the dye, stains-all, with individual calcium-binding domains of calmodulin.
We show that the calcium-mimic dye, Stains-all, is a convenient probe to study the structural features of the individual calcium-binding sites of calmodulin (CaM) and related calcium-binding proteins (CaBP). These peptides bind the dye in their calcium-binding sites, and induce a circular dichroism (CD) band in the bound dye in the 620 nm (J band) region, which is abolished upon the addition of calcium. Replacement of Asp by Asn in the + x position of the weaker calcium-binding site (site I of CaM) abolishes the dye binding, while the same change in the higher affinity site IV attenuates the binding of the dye and does not abolish it. Replacement of Tyr in site IV with Trp does not distort the geometry, although it increases the dye binding affinity.
Sharma
Y
Y
Centre for Cellular and Molecular Biology, Hyderabad, India.
Gopalakrishna
A
A
Balasubramanian
D
D
Fairwell
T
T
Krishna
G
G
D000595:Amino Acid Sequence; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism*; D002232:Carbocyanines / Q000378:metabolism*; D002942:Circular Dichroism; D004396:Coloring Agents / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship
D002147:Calmodulin; D002232:Carbocyanines; D004396:Coloring Agents; D010446:Peptide Fragments; C012040:stains-all; D002118:Calcium