Biochemical Properties of a Novel Cysteine Protease of Plasmodium vivax, Vivapain-4
Figure 4
(A) Superimposition of amino acid residues lining the binding pockets in VX-3 (cyan) and VX-4 (yellow). The residues are shown as sticks and the numbers of residues are indicated in reference to the corresponding enzymes. (B) Mutagenesis of VX-4. Each mutatant was expressed and analyzed by 12% SDS-PAGE (upper) and by a gelatin substrate gel (lower). (C) The activities of wild-type and mutant VX-4s were assayed in 100 mM sodium acetate (pH 5.5) against Z-LR-MCA and 100 mM Tris-HCl (pH 7.5) against Z-RR-MCA at 37°C. In each case, 10 mM DTT was supplemented in reaction buffer. Maximal activity was presented as 100%. Mean ± S.D. (n = 3).