title: High-level expression and characterization of two serine protease inhibitors from Trichinella spiralis.
abstract: Serine protease inhibitors (SPIs) play important roles in tissue homeostasis, cell survival, development, and host defense. So far, SPIs have been identified from various organisms, such as animals, plants, bacteria, poxviruses, and parasites. In this study, two SPIs (Tsp03044 and TspAd5) were identified from the genome of Trichinella spiralis and expressed in Escherichia coli. Sequence analysis revealed that these two SPIs contained essential structural motifs, which were well conserved within the tumor-infiltrating lymphocytes (TIL) and serpin superfamily. Based on protease inhibition assays, the recombinant Tsp03044 showed inhibitory effects on trypsin, α-chymotrypsin, and pepsin, while the recombinant TspAd5 could effectively inhibit the activities of α-chymotrypsin and pepsin. Both these inhibitors showed activity between 28 and 48 °C. The expression levels of the two SPIs were also determined at different developmental stages of the parasite with real-time PCR. Our results indicate that Tsp03044 and TspAd5 are functional serine protease inhibitors.
authors.affiliation: Key Laboratory of Animal Common Disease Prevention, College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, PR China.
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Animal Common Disease Prevention, College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, PR China.
authors.forename: Yixian
authors.initials: Y
authors.lastname: Mao
authors.affiliation: Key Laboratory of Animal Common Disease Prevention, College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, PR China.
authors.forename: Da
authors.initials: D
authors.lastname: Li
authors.affiliation: Key Laboratory of Animal Common Disease Prevention, College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, PR China.
authors.forename: Yvhan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Animal Common Disease Prevention, College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: State Key Laboratory of Veterinary Biotechnology-Michigan State University Joint Laboratory of Innate Immunity, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Maduan Street 427, Nangang District, Harbin 150001, PR China.
authors.forename: Honglin
authors.initials: H
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Veterinary Biotechnology-Michigan State University Joint Laboratory of Innate Immunity, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Maduan Street 427, Nangang District, Harbin 150001, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Animal Common Disease Prevention, College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Key Laboratory of Animal Common Disease Prevention, College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, PR China. Electronic address: luyixin@neau.edu.cn.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D004798:Enzymes / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000494:pharmacology*; D006790:Host-Parasite Interactions; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins / Q000235:genetics; D016415:Sequence Alignment; D015842:Serine Proteinase Inhibitors / Q000235:genetics* / Q000302:isolation & purification / Q000494:pharmacology*; D015843:Serpins / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D013696:Temperature; D017160:Trichinella spiralis / Q000145:classification / Q000235:genetics* / Q000378:metabolism*
chemical_list: D004798:Enzymes; D015801:Helminth Proteins; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; D015843:Serpins
keywords: Chymotrypsin; Pepsin; Serine protease inhibitor; Trichinella spiralis; Trypsin