Intrinsic specificity of Ca²⁺–protein binding sites

Abstract

Abstract The gas‐phase chemistry of anionic [M + Cat 2+ – 3H] − complexes between Ca 2+ ‐specific peptides and the alkaline earth metal ions Mg 2+ , Ca 2+ and Ba 2+ is reported. The metal ion complexes were studied using fast atom bombardment, collision‐induced decomposition (CID) and molecular mechanical calculations. The CID reactions and molecular mechanical calculations revealed that the Ca 2+ –peptide complexes are bound differently to the Mg 2+ – and Ba 2+ –peptide complexes and that the intrinsic (gas‐phase) chemistry is reflected by known aqueousphase chemistry.