Figure 1.

(A) Representation of the trans-dominant mutational strategy used in this study. TR monomers from L. donovani and T. cruzi associated either as homodimers or heterodimers are illustrated showing the essential cysteine and histidine residues that comprise the trypanothione-binding region of the active site. (B) Effect of overexpression of trans-dominant mutants on levels of active enzyme in L. donovani. The extent of inactivation of endogenous TR (Ld/Ld) depends on the level of overexpression of mutant protein (Tc:Ld ratio, r) as described in the text. (Inset) Theoretical relative amounts of each dimer species as a function of heterologous protein overexpression.