Hiding in Plain Sight: The Bimetallic Magnesium Covalent Bond in Enzyme Active Sites.

ABSTRACT: The transfer of phosphate groups is an essential function of many intracellular biological enzymes. The transfer is in many cases facilitated by a protein scaffold involving two closely spaced magnesium "ions". It has long been a mystery how these "ions" can retain their closely spaced positions throughout enzymatic phosphate transfer: Coulomb's law would dictate large repulsive forces between these ions at the observed distances. Here we show, however, that the electron density can be borrowed from nearby electron-rich oxygens to populate a bonding molecular orbital that is largely localized between the magnesium "ions". The result is that the Mg-Mg core of these phosphate transfer enzymes is surprisingly similar to a metastable [Mg₂]²⁺ ion in the gas phase, an ion t

SUBMITTER: Perera L 

PROVIDER: S-EPMC5573160 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature