Strontium Binding to α-Parvalbumin, a Canonical Calcium-Binding Protein of the "EF-Hand" Family.

ABSTRACT: Strontium salts are used for treatment of osteoporosis and bone cancer, but their impact on calcium-mediated physiological processes remains obscure. To explore Sr2+ interference with Ca2+ binding to proteins of the EF-hand family, we studied Sr2+/Ca2+ interaction with a canonical EF-hand protein, α-parvalbumin (α-PA). Evaluation of the equilibrium metal association constants for the active Ca2+ binding sites of recombinant human α-PA ('CD' and 'EF' sites) from fluorimetric titration experiments and isothermal titration calorimetry data gave 4 × 109 M-1 and 4 × 109 M-1 for Ca2+, and 2 × 107 M-1 and 2 × 106 M-1 for Sr2+. Inactivation of the EF site by homologous substitution of the Ca2+-coordinating Glu in position 12 of the EF-loop by Gln decreased Ca2+/Sr2+ affinity of the protein by an o

SUBMITTER: Vologzhannikova AA 

PROVIDER: S-EPMC8392015 | biostudies-literature | 2021 Aug

REPOSITORIES: biostudies-literature