there are also rare examples of naturally occurring polypeptides that appear to be a fusion of two clearly defined modules, in which each module displays its characteristic activity or function, independent of the other. two major examples are: double pp2c chimera in "plasmodium falciparum" (the malaria parasite), in which each pp2c module exhibits protein phosphatase 2c enzymatic activity, and the dual-family immunophilins that occur in a number of unicellular organisms (such as protozoan parasites and flavobacteria) and contain full-length cyclophilin and fkbp chaperone modules. the evolutionary origin of such chimera remains unclear.