Metalloantibodies: mercury(II)-dependent acyl transferases Original Research Article

A new approach for the elicitation of metal-dependent catalytic antibodies for ester hydrolysis is described. A coordinatively unsaturated mercury complex 1-(Hg), has been utilized as a hapten to elicit antibodies that incorporate mercury(II) as a Lewis acid cofactor. From a panel of monoclonal antibodies generated to 1-(Hg), antibody 38G2 was found to hydrolyze the ester 3 in the presence of HgCl2 [Kmapp(3)=345 μM; Kmapp(Hg2+)=87 μM; kcatapp/kuncat=3×102]. This is the first example of a biocatalyst that enlists mercuric ion as a cofactor and it is anticipated that this approach will open new avenues for exploitation of metals thought previously beyond the scope of protein catalysts.