High resolution crystal structures of triosephosphate isomerase complexed with its suicide inhibitors: The conformational flexibility of the catalytic glutamate in its closed, liganded active site

The key residue of the active site of triosephosphate isomerase (TIM) is the catalytic glutamate, which is proposed to be important (i) as a catalytic base, for initiating the reaction, as well as (ii) for the subsequent proton shuttling steps. The structural properties of this glutamate in the liganded complex have been investigated by studying the high resolution crystal structures of typanosomal TIM, complexed with three suicide inhibitors: (S)-glycidol phosphate ((S)-GOP, at 0.99 A resolution), (R)-glycidol phosphate, ((R)-GOP, at 1.08 A resolution), and bromohydroxyacetone phosphate (BHAP, at 1.97 A resolution). The structures show that in the (S)-GOP active site this catalytic glutama…