A novel gene encoding a thrombin inhibitory protein in a cDNA library from Haemaphysalis longicornis salivary gland.
A novel thrombin inhibitory protein coding gene was identified from a cDNA library derived from salivary gland of partially-fed Haemaphysalis longicornis (hard tick). The gene encoded a 93-amino acid protein, designated chimadanin, which had a signal peptide sequence and was predicted to be a secretory protein. It showed no similarity to any other previously identified proteins or conserved domain sequences. The gene was expressed during blood feeding and suggested to be expressed mainly in the salivary gland. The predicted mature region of chimadanin was expressed in Escherichia coli and characteristics of the recombinant chimadanin were determined. The activated partial thromboplastin time and the prothrombin time in sheep plasma were significantly prolonged by chimadanin in a dose dependent manner. Amidolytic activity of thrombin was also inhibited by chimadanin in a dose dependent manner and it suggested that chimadanin was an anticoagulant with thrombin inhibitory activity. This newly identified thrombin inhibitor may play an important role in tick blood feeding.
Nakajima
Chie
C
Laboratory of Infectious Diseases, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Japan.
Imamura
Saiki
S
Konnai
Satoru
S
Yamada
Shinji
S
Nishikado
Hideto
H
Ohashi
Kazuhiko
K
Onuma
Misao
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005247:Feeding Behavior / Q000502:physiology; D020869:Gene Expression Profiling / Q000662:veterinary; D015723:Gene Library; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D026863:Ixodidae / Q000235:genetics* / Q000502:physiology*; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis / Q000662:veterinary; D010314:Partial Thromboplastin Time / Q000662:veterinary; D011517:Prothrombin Time / Q000662:veterinary; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D012469:Salivary Glands / Q000737:chemistry; D012471:Salivary Proteins and Peptides / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D012756:Sheep; D013917:Thrombin / Q000037:antagonists & inhibitors* / Q000378:metabolism
D019476:Insect Proteins; D011994:Recombinant Proteins; D012471:Salivary Proteins and Peptides; C517571:chimadanin; D013917:Thrombin