... CG2, the lack of clear homology outside these regions, and the unique tripeptidase speci®city of peptidase T, suggested that the structure of the two enzymes would in part differ. Wereport the ... while the Ne2 atom is hydrogenbonded to a n aspartic acid residue, albeit from a differentpart of the structure. The role of the t hreonine residue in the HXDT motif is less obvious, but the ... peptides [1].Many of these e nzymes h ave been shown to function in the degradation of intracellular proteins and in the catabolism of exogenously supplied p eptides [2]. O ne of these enzymes,peptidase...