title: Characterization of a novel serine protease inhibitor gene from a marine metagenome.
abstract: A novel serine protease inhibitor (serpin) gene designated as Spi1C was cloned via the sequenced-based screening of a metagenomic library from uncultured marine microorganisms. The gene had an open reading frame of 642 base pairs, and encoded a 214-amino acid polypeptide with a predicted molecular mass of about 28.7 kDa. The deduced amino acid sequence comparison and phylogenetic analysis indicated that Spi1C and some partial proteinase inhibitor I4 serpins were closely related. Functional characterization demonstrated that the recombinant Spi1C protein could inhibit a series of serine proteases. The Spi1C protein exhibited inhibitory activity against α-chymotrypsin and trypsin with K(i) values of around 1.79 × 10(-8) and 1.52 × 10(-8) M, respectively. No inhibition activity was exhibited against elastase. Using H-d-Phe-Pip-Arg-pNA as the chromogenic substrate, the optimum pH and temperature of the inhibition activity against trypsin were 7.0-8.0 and 25 °C, respectively. The identification of a novel serpin gene underscores the potential of marine metagenome screening for novel biomolecules.
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue East Road, Nanning, Guangxi 530004, China.
authors: Cheng-Jian
authors: CJ
authors: Jiang
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue East Road, Nanning, Guangxi 530004, China.
authors: Zhen-Yu
authors: ZY
authors: Hao
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue East Road, Nanning, Guangxi 530004, China.
authors: Rong
authors: R
authors: Zeng
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue East Road, Nanning, Guangxi 530004, China.
authors: Pei-Hong
authors: PH
authors: Shen
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue East Road, Nanning, Guangxi 530004, China.
authors: Jun-Fang
authors: JF
authors: Li
authors: College of Chemistry and Ecology Engineering, Guangxi University for Nationalities, 188 Daxue East Road, Nanning, Guangxi 530006, China.
authors: Bo
authors: B
authors: Wu
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D054892:Metagenome; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000494:pharmacology; D015842:Serine Proteinase Inhibitors / Q000235:genetics* / Q000302:isolation & purification / Q000494:pharmacology; D014871:Water Microbiology
chemical_list: D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors