Characterization of a carboxypeptidase inhibitor from the tick Haemaphysalis longicornis.
A carboxypeptidase inhibitor called HlTCI was isolated from Haemaphysalis longicornis in this study. The full-length cDNA of HlTCI contains an open reading frame (ORF) of 291bp, encoding 96 amino acid residues consisting of a predicted 19-residue signal peptide and a putative mature 77-residue protein. The expected mature protein is cysteine-rich and has 12 cysteine residues assumed to construct six disulfide bridges. The deduced peptide sequence shows 63.9% homology to the carboxypeptidase inhibitor from another ixodid tick, Rhipicephalus bursa. Reverse-transcription PCR (RT-PCR) indicated that HlTCI was specifically expressed in the ovary from partially engorged adult ticks. The recombinant protein of HlTCI (rHlTCI) with glutathione S-transferase (GST) was expressed in Escherichia coli strain BL21 (DE3) and purified by glutathione-Sepharose 4B beads. rHlTCI showed inhibitory activity against digestive metallocarboxypeptidases A and B, but the activity was affected by the increase of the temperature treatment. High concentrations of rHlTCI were shown to significantly accelerate fibrinolysis in vitro. This effect of rHlTCI on clot lysis suggests its promising potential for use in some thrombotic disorders.
Gong
Haiyan
H
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan.
Zhou
Jinlin
J
Liao
Min
M
Hatta
Takeshi
T
Harnnoi
Thasaneeya
T
Umemiya
Rika
R
Inoue
Noboru
N
Xuan
Xuenan
X
Fujisaki
Kozo
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002268:Carboxypeptidases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D003001:Cloning, Molecular; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D005260:Female; D005342:Fibrinolysis / Q000187:drug effects; D006801:Humans; D026863:Ixodidae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008969:Molecular Sequence Data; D012313:RNA / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment
D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D012313:RNA; D002268:Carboxypeptidases