Many-body effect determines the selectivity for Ca²⁺ and Mg²⁺ in proteins.

ABSTRACT: Calcium ion is a versatile messenger in many cell-signaling processes. To achieve their functions, calcium-binding proteins selectively bind Ca²⁺ against a background of competing ions such as Mg²⁺ The high specificity of calcium-binding proteins has been intriguing since Mg²⁺ has a higher charge density than Ca²⁺ and is expected to bind more tightly to the carboxylate groups in calcium-binding pockets. Here, we showed that the specificity for Ca²⁺ is dictated by the many-body polarization effect, which is an energetic cost arising from the dense packing of multiple residues around the metal ion. Since polarization has stronger distance dependence compared with permanent electrostatics, the cost associated with the smaller Mg²⁺

SUBMITTER: Jing Z 

PROVIDER: S-EPMC6094099 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature