Entry M0277 18.104.22.168 mercury(II) reductase
The distal sulfur of Cys11 acts as a nucleophile towards the Hg(II) complex.
Comment: The catalytic centre is activated towards its function in the presence of NADPH. The group reduces a disulfide bond between Cys141 and Cys136, forming the dithiol species which is necessary for catalysis to occur. A charge transfer complex exists between the FAD cofactor and Cys141 .
The two N terminal Cys residues (Cys11/Cys14) form part of a soft-metal binding domain. The positive charge of the N terminus, as well as the presence of specific interactions with surrounding residues lowers the pKa of these cysteine thiols relative to unstructured peptide analogues, enhancing their nucleophilic character and therefore their reactivity with Hg over other peptide sequences.
Amino acids involved in the reaction step.
Organic Cofactors involved in the reaction step
Metal Cofactors involved in Step 01
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