Design, creation, and characterization of a stable, monomeric triosephosphate isomerase.

Protein engineering on trypanosomaltriosephosphate isomerase (TIM) converted this oligomeric enzyme into a stable,monomeric protein that is enzymatically active. Wild-type TIM consists of twoidentical subunits that form a very tight dimer involving interactions of 32residues of each subunit. By replacing 15 residues of the major interface loopby another 8-residue fragment, a variant was constructed that is a stable andmonomeric protein with TIM activity. The length, sequence, and conformation ofthe designed fragment were suggested by extensive modeling.