PRIMARY STRUCTURE AND PARTIAL CHARACTERIZATION OF A LIFE-CYCLE-REGULATED CYSTEINE PROTEASE FROM TRYPANOSOMA (NANNOMONAS) CONGOLENSE

Trypanosoma (Nannomonas) congolense is an important pathogenic parasit e of domestic livestock in Africa. We have cloned a cDNA encoding a pr epro-cysteine protease of this protozoan, the sequence of which indica tes it is an early mRNA processing intermediate. Northern analysis dem onstrates a life-cycle-stage specificity similar to previously describ ed enzymatic data. The deduced amino-acid sequence shows extensive sim ilarity to cysteine proteases of other parasitic protozoa, as well as papain and cathepsin L. As with other African trypanosomes, a poly-pro line tract connects the catalytic domain with an unusual C-terminal ex tension,