Molecular cloning and characterization of copper/zinc-superoxide dismutase of Paragonimus westermani.
Superoxide dismutases (SODs; EC 1.15.1.1) play important roles in the protection of the parasites against cellular oxygen-mediated killing of the hosts. A copper/zinc-containing SOD (Cu/Zn-SOD) was identified previously from lung fluke, Paragonimus westermani. To expand our understanding of P. westermani SOD, we isolated a complementary DNA encoding a Cu/Zn-SOD, expressed the active enzyme in Escherichia coli, and characterized its biochemical properties. The deduced amino acid (aa) sequence of the gene shared up to 73.7% identities with Cu/Zn-SODs of other helminths and shared well-conserved characteristic motifs and essential aa residues involved in coordinating copper and zinc enzymatic functions. Recombinant Cu/ Zn-SOD exhibited comparable biochemical properties with that of the native enzyme, including pH optima and potassium cyanide-and hydrogen peroxide-sensitive inhibition profiles. The active enzyme consisted of 2 identical subunits covalently linked by disulfide bonds. The enzyme was constitutively expressed throughout various developmental stages of the parasite. The levels increased as P. westermani matured and plateaued in adult stage. Our result suggests the enzyme might play an important role for parasites to survive in the hosts through its superoxide anion-detoxifying function.
Department of Tropical and Endemic Parasitic Diseases, National Institute of Health, Seoul 122-701, Korea.
Ai-Hua
AH
Li
Byoung-Kuk
BK
Na
Yoon
Y
Kong
Shin-Hyeong
SH
Cho
Qin-Ping
QP
Zhao
Tong-Soo
TS
Kim
D000595:Amino Acid Sequence; D000818:Animals; D003400:Astacoidea; D001483:Base Sequence; D002415:Cats; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D018509:DNA, Helminth / Q000737:chemistry*; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D008970:Molecular Weight; D048492:Paragonimus westermani / Q000201:enzymology* / Q000235:genetics; D018510:RNA, Helminth / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics*
D018076:DNA, Complementary; D018509:DNA, Helminth; D018510:RNA, Helminth; D011994:Recombinant Proteins; D013482:Superoxide Dismutase