Post-translational activation introduces a free radical into pyruvate formate-lyase

摘要: Abstract Pyruvate formate-lyase (formate acetyltransferase; EC 2.3.1.54) of Escherichia coli cells is post-translationally interconverted between inactive and active forms. Conversion the to form catalyzed by an Fe2+-dependent activating enzyme requires adenosylmethionine dihydroflavodoxin. This process shown here introduce a paramagnetic moiety into structure pyruvate formate-lyase. It displays EPR signal at g = 2 with doublet splitting 1.5 mT could comprise organic free radical located on amino acid residue polypeptide chain. Hypophosphite was discovered as specific reagent that destroys both activity; it becomes covalently bound protein. The enzymatic generation radical, which linked cleavage 5'-deoxyadenosine methionine, possibly occurs through Fe-adenosyl complex. These results suggest mechanism for catalytic cycle