This is a highly conserved sequence motif that is the very C-terminus of a number of more diverse proteins from Trypanosoma cruzi. All members of the family are annotated putatively as being trans-sialidase but this appears to be a diverse group.

1: The high resolution structures of free and inhibitor-bound Trypanosoma rangeli sialidase and its comparison with T. cruzi trans-sialidase. Amaya MF, Buschiazzo A, Nguyen T, Alzari PM; J Mol Biol. 2003;325:773-784. PMID:12507479