Processing of pro-thrombostasin by a recombinant subtilisin-like proprotein convertase derived from the salivary glands of horn flies (Haematobia irritans).
Thrombostasin (TS) is a thrombin inhibitor found in the salivary glands of horn flies (Haematobia irritans). It is produced as an inactive form with a 76-amino acid propeptide in the N-terminus preceding the mature TS. A minimal recognition sequence by subtilisin-like proprotein convertases, Arg-Xaa-Xaa-Arg, is localized C-terminal to the propeptide. This study demonstrated that a gene cloned from the salivary glands of the horn fly encodes a new convertase, subsequently named horn fly proprotein convertase (HFPC), and that the recombinant HFPC expressed in insect HighFive cell culture specifically cleaves recombinant pro-thrombostasin, produced in E. coli, at the expected site. The relative cleavage efficiency of rHFPC was compared with that of recombinant human furin, a commercially available proprotein convertase. The result indicated that this newly identified proprotein convertase is of importance for the proteolytic maturation of thrombostasin, a protein secreted in horn fly saliva and used by the insect to counteract its host's haemostatic response.
Zhang
Dunhua
D
Department of Entomology and Plant Pathology, 301 Funchess Hall, Auburn University, Auburn, AL 36849, USA. duzhang@acesag.auburn.edu
Cupp
Mary S
MS
Cupp
Ed W
EW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D019476:Insect Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009117:Muscidae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D043484:Proprotein Convertases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012469:Salivary Glands / Q000201:enzymology
D019476:Insect Proteins; D011498:Protein Precursors; D011994:Recombinant Proteins; C439004:Thrombostasin protein, Haematobia irritans; D043484:Proprotein Convertases