Noncovalent modulation of pH-dependent reactivity of a Mn-salen cofactor in myoglobin with hydrogen peroxide.

ABSTRACT: To demonstrate protein modulation of metal-cofactor reactivity through noncovalent interactions, pH-dependent sulfoxidation and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) oxidation reactivity of a designed myoglobin (Mb) containing non-native Mn-salen complex (1) was investigated using H2O2 as the oxidant. Incorporation of 1 inside the Mb resulted in an increase in the turnover numbers through exclusion of water from the metal complex and prevention of Mn-salen dimer formation. Interestingly, the presence of protein in itself is not enough to confer the increase activity as mutation of the distal His64 in Mb to Phe to remove hydrogen-bonding interactions resulted in no increase in the turnover numbers, while mutation His64 to Arg, another residue with ability to hydrogen

SUBMITTER: Zhang JL 

PROVIDER: S-EPMC2777979 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature