食品科学 ›› 2017, Vol. 38 ›› Issue (16): 86-91.doi: 10.7506/spkx1002-6630-201716013

• 生物工程 • 上一篇    下一篇

N-糖基化对β-甘露聚糖酶在毕赤酵母中异源表达的影响

马清,蔡瑞,姜风超,马立娟,杜丽平,肖冬光   

  1. (1.天津科技大学生物工程学院,工业发酵微生物教育部重点实验室,天津 300457;2.天津食品安全低碳制造协同创新中心,天津 300457)
  • 出版日期:2017-08-25 发布日期:2017-08-18
  • 基金资助:
    天津科技大学青年教师创新基金项目(2014CXLG10);工业发酵微生物教育部重点实验室暨天津市工业微生物重点实验室(天津科技大学)开放基金项目(2014IM101);天津市自然科学基金重点项目(16JCZDJC31800)

Effect of N-Glycosylation on the Heterologous Expression of β-Mannanase in Pichia pastoris

MA Qing, CAI Rui, JIANG Fengchao, MA Lijuan, DU Liping, XIAO Dongguang   

  1. (1. Key Laboratory of Industrial Microbiology, Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; 2. Tianjin Food Safety & Low Carbon Manufacturing Collaborative Innovation Center, Tianjin 300457, China)
  • Online:2017-08-25 Published:2017-08-18

摘要: 为研究N-糖基化对里氏木霉β-甘露聚糖酶(β-mannanase,Man1)在毕赤酵母GS115中异源表达的影响, 采用定点突变的方法,将Man1上3 个N-糖基化修饰位点(N131、N158和N329)上的天冬酰胺用中性谷氨酰胺取 代。结果发现,N-糖基化位点的突变对Man1的转录水平无明显影响,突变后获得的Man1表观分子质量有轻微下 降,与Man1相比,3 个突变体N131、N158和N329的甘露聚糖酶活力分别降低了85.43%和79.48%和16.3%;而热稳 定性分别提高了7.87%、13.5%和15.37%。由此可见,N-糖基化修饰对于β-甘露聚糖酶的高效表达是必需的,其中 N131和N158糖基化位点尤为重要,但是会稍微降低β-甘露聚糖酶的热稳定性。

关键词: β-甘露聚糖酶, N-糖基化, 定点突变, 酶活力, 热稳定性

Abstract: In order to investigate the influence of N-glycosylation on the expression of β-mannanase from Trichoderma reesei (Man1) in Pichia pastoris GS115, the asparagine (Asn) residues at three N-linked glycosylation sites (N131, N158 and N329) of Man1 were substituted by neutral glutamine (Gln) through site-directed mutagenesis. The results showed that mutations of the N-glycosylated sites had no significant effects on the expression of Man1 at the transcriptional level. Compared with Man1, the apparent molecular mass of the mutant Man1 decreased slightly, and the activities of the mutants (N131, N158 and N329) decreased by 85.43%, 79.48% and 16.3%, respectively. However, the thermal stability of mutant N131, N158 and N329 increased by 7.87%, 13.5% and 15.37% compared to that of Man1. Therefore, N-glycosylation especially at N131 and N158 was essential for the high-level expression of Man1 in P. pastoris GS115, but led to a slight reduction in the thermal stability of Man1.

Key words: β-mannanase, N-glycosylation, site-directed mutagenesis, enzyme activity, thermal stability

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