生物技术通报 ›› 2020, Vol. 36 ›› Issue (1): 23-28.doi: 10.13560/J.cnki.biotech.bull.1985.2019-0529

• 研究报告 • 上一篇    下一篇

氨基酸定点突变提高灵芝蛋白LZ-8热稳定性的研究

孙熙麟1, 蒋振彦1, 刘志屹2, 戴璐2, 孙非2, 黄伟2   

  1. 1. 吉林大学药学院,长春 130021;
    2. 吉林大学再生医学科学研究所,长春 130021
  • 收稿日期:2019-06-10 出版日期:2020-01-26 发布日期:2020-01-08
  • 作者简介:孙熙麟,女,博士,研究方向:生物制药;E-mail:sunxilin@jlu.edu.cn
  • 基金资助:
    吉林省科技成果转化计划(201603064YY),吉林省科技攻关计划(20150204048YY),吉林省科技创新人才培育计划(20160520042JH)

Improvement of Thermal Stability of Ganoderma lucidum Protein LZ-8 by Site-directed Mutation of Amino Acids

SUN Xi-lin1, JIANG Zhen-yan1, LIU Zhi-yi2, DAI Lu2, SUN Fei2, HUANG Wei2   

  1. 1. School of Pharmacy,Jilin University,Changchun 130021;
    2. Institute of Frontier Medical Science,Jilin University,Changchun 130021
  • Received:2019-06-10 Published:2020-01-26 Online:2020-01-08

摘要: 通过氨基酸定点突变技术提高灵芝免疫调节蛋白LZ-8的热稳定性。通过分子动力学模拟结合温度因子预测对LZ-8氨基酸突变位点进行理性设计,在毕赤酵母X33菌株内构建并表达LZ-8突变体蛋白,采用HeLa细胞生长抑制实验和差示量热扫描分析检测并比较了LZ-8突变前后生物学活性及热力学参数。结果显示,LZ-8 N-端α螺旋为理论预测的温度敏感区域,在该区域进行F8W和R9K氨基酸双位点突变,突变后的LZ-8热稳定性提高,相变温度Tm上升0.92℃,相转变焓值ΔH提高23.14 kJ/mol,但突变后LZ-8生物学活性基本不变,LZ-8和LZ-8突变体对HeLa细胞生长抑制的IC50值分别是2.238 μg/mL 和2.407 μg/mL。通过理性设计氨基酸突变位点,获得了稳定性提高但生物学活性不变的灵芝免疫调节蛋白LZ-8的突变体。

关键词: LZ-8, 热稳定性, 分子动力学模拟, 温度因子, 定点突变

Abstract: This work is to improve the thermal stability of Ganoderma lucidum immunoregulatory protein LZ-8 by site-directed mutagenesis of amino acids. Molecular dynamics simulation combined with temperature factor prediction were used to reasonably design LZ-8 amino acid mutation site,LZ-8 mutant protein was constructed and expressed in Pichia pastoris X33 strain,the biological activity and thermodynamic parameters of LZ-8 before and after mutation were detected and compared by HeLa cell growth inhibition experiment and differential scanning calorimetric(DSC)study. Results showed that LZ-8 N-terminal alpha helix was the temperature sensitive region predicted by theory. F8W and R9K double site mutations occurred in this region. After mutation,the thermal stability of LZ-8 was improved,the phase transition temperature Tm increased by 0.92℃,and the phase transition enthalpy ΔH increased by 23.14 kJ/mol. However,the biological activity of LZ-8 after mutation was basically unchanged. The IC50 of LZ-8 and LZ-8 mutant on HeLa cell growth inhibition was 2.238 μg/mL and 2.407 μg/mL,respectively. Ganoderma lucidum LZ-8 mutant with improved stability but unchanged biological activity is obtained by rational design of amino acid mutation sites.

Key words: LZ-8, thermal stability, molecular dynamics simulation, temperature factor, site-directed mutation