Identification and characterization of a serine protease inhibitor with two trypsin inhibitor-like domains from the human hookworm Ancylostoma duodenale.
Protease inhibitors play important roles in the parasitic nematodes' survival within their host, in the development and reproduction of the parasites. The present study described the isolation, identification, and characterization of a novel member of the Ascaris family of serine protease inhibitors, designated AduTIL-1, from the human hookworm Ancylostoma duodenale. AduTIL-1 is composed of a signal sequence and two trypsin inhibitor-like (TIL) domains, which showed the highest similarity with OdmCRP, a putative serine protease inhibitor with two TIL domains in Oesophagostomum dentatum. Each TIL domain of the AduTIL-1 was expressed in Escherichia coli, and their inhibitory activities against serine proteases from animals and human were characterized, respectively. Both of the two TIL domains inhibited human neutrophil elastase and pancreatic trypsin, but different in effectiveness. Although the first TIL domain of AduTIL-1 inhibited bovine pancreatic chymotrypsin (Ki=18.0 nM), both of the two domains showed no inhibitory activity against the human pancreatic chymotrypsin. Immunohistochemical studies demonstrated that AduTIL-1 was localized in esophagus, intestine, and cuticular surface of the adult worms. These results suggested that AduTIL-1 may be involved in the survival of A. duodenale in host by targeting related digestive enzymes and neutrophil elastase.
Jin
Xian
X
Department of Parasitology and Clinical Parasitology, Guangdong Medical College, 2 Wenming East Street, Xiashan District, Zhanjiang, Guangdong Province, 524023, People's Republic of China.
Deng
Li
L
Li
Hui
H
Zhang
Zhenlin
Z
He
Qingfeng
Q
Yang
Chen
C
Jiang
Hanguo
H
Zhu
Xing-Quan
XQ
Peng
Lifei
L
D000595:Amino Acid Sequence; D000722:Ancylostoma / Q000033:anatomy & histology / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D017238:Genes, Helminth; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D006790:Host-Parasite Interactions; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors; D010802:Phylogeny; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D014361:Trypsin Inhibitors / Q000235:genetics
D018076:DNA, Complementary; D015801:Helminth Proteins; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; C557999:TIL-1 protein, Ancylostoma duodenale; D014361:Trypsin Inhibitors; D010196:Pancreatic Elastase