Chohnan Shigeru, Nonaka Junko, Teramoto Kousei, Taniguchi Kouichi, Kameda Yuuko, Tamura Hitoshi, Kurusu Yasurou, Norioka Shigemi, Masaki Takeharu, Sakiyama Fumio
Department of Bioresource Science, College of Agriculture, Ibaraki University, 3-21-1 Chu-ou, Ami, Ibaraki, Japan.
FEMS Microbiol Lett. 2002 Jul 16;213(1):13-20. doi: 10.1111/j.1574-6968.2002.tb11279.x.
A new lysyl endopeptidase producing strain, Lysobacter sp. IB-9374, was isolated from soil. This strain secreted the endopeptidase to culture medium at 6-12-fold higher levels relative to Achromobacter lyticus and Lysobacter enzymogenes. The mature Lysobacter sp. enzyme was enzymatically identical to Achromobacter lysyl endopeptidase bearing lysyl bond specificity, a high peptidase activity, a wide pH optimum, and stability against denaturants. Nucleotide sequence analysis of the Lysobacter sp. lysyl endopeptidase gene revealed that the enzyme is synthesized as a precursor protein consisting of signal peptide (20 amino acids (aa)), pro-peptide (185 aa), mature enzyme (268 aa), and C-terminal extension peptide (198 aa). The deduced amino acid sequence of the mature enzyme was totally identical to that of the Achromobacter enzyme. The Lysobacter sp. precursor protein has an 18-aa longer peptide chain following nine consecutive amino acid residues distinct from the Achromobacter counterpart at the C-terminus. Total precursor protein is 671 aa of which only 268 aa are in the finally processed exoenzyme.
从土壤中分离出一种新的产赖氨酰内肽酶菌株——溶杆菌属IB-9374。相对于溶菌无色杆菌和产酶溶杆菌，该菌株向培养基中分泌内肽酶的水平要高6至12倍。成熟的溶杆菌属酶在酶学性质上与具有赖氨酰键特异性、高肽酶活性、较宽的最适pH值以及对变性剂稳定的溶菌无色杆菌赖氨酰内肽酶相同。对溶杆菌属赖氨酰内肽酶基因的核苷酸序列分析表明，该酶以前体蛋白的形式合成，前体蛋白由信号肽（20个氨基酸（aa））、前肽（185 aa）、成熟酶（268 aa）和C端延伸肽（198 aa）组成。推导的成熟酶氨基酸序列与溶菌无色杆菌的酶完全相同。溶杆菌属前体蛋白在C端有一段由9个连续氨基酸残基组成的肽链，比溶菌无色杆菌的对应肽链长18个氨基酸。前体蛋白全长671个氨基酸，而最终加工后的胞外酶只有268个氨基酸。
