using a series of homologous calcium-binding proteins , a quantitative structure-activity relationship ( qsar ) , log ( 1/kd ) = -18.986 - 1.6278 ( x1 ) + 0.7981 ( x2 ) + 0.2312 ( x3 ) , has been established , which relates the calcium-binding affinities ( 1/kd ) of the regulatory proteins with ( i ) the net ligand charge ( x1 ) of the two calcium binding loops , ( ii ) the hydrophobicity ( x2 ) of the beta-sheet segment of the loops and ( iii ) the hydrophobicity ( x3 ) of the four 'ef-hand ' helices .
C0006732
calcium-binding proteins
C1516144
calcium binding