Figure 3
Cysteine pair at the THF binding pocket. (a) Conformation of loop-Cys125 and loop-Cys364 at the THF binding pocket of PfSHMT, controlled by the reduction state of the cysteine pair Cys125 and Cys364. The disulfide bond in pink and the corresponding sulfhydryl groups in green of Cys125 and Cys364 control the movement of the surface loop-Cys125 and loop-Cys364 (residues 126–143 and 356–369, respectively) critical for PfSHMT functional activity. (b) Superposition of PfSHMT1 (pink), PfSHMT2 (green) and EcSHMT (PDB entry 1dfo
; white) showing the THF pocket and bound 5FTHF from the EcSHMT structure. A conformational change of loop-Cys364 towards the THF binding pocket promoted the binding of the THF substrate in the active sulfhydryl enzyme (in green). |