Gu Yanyan, Wang Xiaomeng, Yang Chao, Geng Weitao, Feng Jun, Wang Yuanyuan, Wang Shufang, Song Cunjiang
Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China.
State Key Laboratory of Medicinal Chemical Biology, Nankai University, 94 Weijin Road, Tianjin, 300071, China.
Appl Biochem Biotechnol. 2016 Apr;178(7):1445-57. doi: 10.1007/s12010-015-1958-7. Epub 2016 Jan 9.
ε-Poly-L-lysine (ε-PL) is a widely used natural food preservative. To test the effects of the Vitreoscilla hemoglobin (VHb) and S-adenosylmethionine (SAM) on ε-PL synthesis in Streptomyces albulus NK660, the heterologous VHb gene (vgb) and SAM synthetase gene (metK) were inserted into the S. albulus NK660 chromosome under the control of the constitutive ermE* promoter. CO-difference spectrum analysis showed S. albulus NK660-VHb strain could express functional VHb. S. albulus NK660-VHb produced 26.67 % higher ε-PL and 14.57 % higher biomass than the wild-type control, respectively. Reversed-phase high-pressure liquid chromatography (RP-HPLC) results showed the overexpression of the metK gene resulted in increased intracellular SAM synthesis in S. albulus NK660-SAM, which caused increases of biomass as well as the transcription level of ε-PL synthetase gene (pls). Results indicated that the expression of vgb and metK gene improved on ε-PL synthesis and biomass for S. albulus NK660, respectively.
ε-聚-L-赖氨酸（ε-PL）是一种广泛使用的天然食品防腐剂。为了测试透明颤菌血红蛋白（VHb）和S-腺苷甲硫氨酸（SAM）对白色链霉菌NK660中ε-PL合成的影响，将异源VHb基因（vgb）和SAM合成酶基因（metK）在组成型ermE*启动子的控制下插入到白色链霉菌NK660染色体中。CO差光谱分析表明，白色链霉菌NK660-VHb菌株能够表达功能性VHb。白色链霉菌NK660-VHb产生的ε-PL比野生型对照分别高26.67%，生物量高14.57%。反相高压液相色谱（RP-HPLC）结果表明，metK基因的过表达导致白色链霉菌NK660-SAM中细胞内SAM合成增加，这导致生物量以及ε-PL合成酶基因（pls）转录水平的增加。结果表明，vgb和metK基因的表达分别提高了白色链霉菌NK660的ε-PL合成和生物量。
