Redox sensitive cysteine residues in calbindin D28k are structurally and functionally important.

Human calbindin D(28k) is a Ca(2+) binding protein that has been implicated in the protection of cells against apoptosis. In this study, the structural and functional significance of the five cysteine residues present in this protein have been investigated through a series of cysteine-to-serine mutations. The mutants were studied under relevant physiological redox potentials in which conformational changes were monitored using ANS binding.