Metacaspase 2 of Trypanosoma brucei is a calcium-dependent cysteine peptidase active without processing.
Metacaspases are cysteine peptidases that are distantly related to the caspases, for which proteolytic processing is central to their activation. Here, we show that recombinant metacaspase 2 (MCA2) from Trypanosoma brucei has arginine/lysine-specific, Ca(2+)-dependent proteolytic activity. Autocatalytic processing of MCA2 occurred after Lys55 and Lys268; however, this was shown not to be required for the enzyme to be proteolytically active. The necessity of Ca(2+), but not processing, for MCA2 enzymatic activity clearly distinguishes MCA2 from the caspases and would be consistent with different physiological roles.
Moss
Catherine X
CX
Wellcome Centre for Molecular Parasitology and Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK.
Westrop
Gareth D
GD
Juliano
Luiz
L
Coombs
Graham H
GH
Mottram
Jeremy C
JC
D000818:Animals; D001120:Arginine / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D020169:Caspases / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D015800:Protozoan Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000378:metabolism
D015800:Protozoan Proteins; D011994:Recombinant Proteins; D001120:Arginine; D020169:Caspases; D003546:Cysteine Endopeptidases; D008239:Lysine; D002118:Calcium