食品科学 ›› 2025, Vol. 46 ›› Issue (19): 116-123.doi: 10.7506/spkx1002-6630-20250203-004

• 生物工程 • 上一篇    

天然乳酸乳球菌硒蛋白表达机制及酶活特性

彭静静,岳世阳,卢良华,刘小玲,王成华   

  1. (1.广西卫生职业技术学院,广西 南宁 530023;2.广西大学轻工与食品工程学院,广西 南宁 530004)
  • 发布日期:2025-09-16
  • 基金资助:
    国家自然科学基金面上项目(31972050);广西卫生职业技术学院高层次人才专项(GXWZY202303)

Mechanism of Selenoprotein Expression and Enzymatic Activity Characteristics in Natural Lactococcus lactis

PENG Jingjing, YUE Shiyang, LU Lianghua, LIU Xiaoling, WANG Chenghua   

  1. (1. Guangxi Health Science College, Nanning 530023, China;2. College of Light Industry and Food Engineering, Guangxi University, Nanning 530004, China)
  • Published:2025-09-16

摘要: 通过构建Lactococcus lactis NZ9000/pNZ8148-GPx基因重组菌(简称NG1)以及分别在LlGPx(即NG1表达的谷胱甘肽过氧化物酶(glutathione peroxidase,GPx)的3 个半胱氨酸位点(C36、C63、C81)和倒数第2个赖氨酸位点(L156)引入编码硒代半胱氨酸(selenocysteine,Sec)的终止密码子UGA和硒代半胱氨酸插入元件(selenocysteine insertion sequence,SECIS)构建产特异性硒蛋白突变株,探讨天然乳酸乳球菌对含Sec硒蛋白的表达情况并分析它们在无诱导、乳酸链球菌素(Nisin)诱导和富硒诱导条件下的LlGPx活性差异。结果显示,LlGPx突变体构建成功,富硒诱导下LlGPx活性为89.10 mU/mg,突变体的GPx活性为56.17~84.45 mU/mg,两者差异小;经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析,野生型对照菌NG1在17.8 kDa的位置有一显著条带,而突变株均没有出现显著的硒蛋白完整或截短条带,说明在乳酸菌NZ9000内只引入UGA和SECIS时,UGA不能被有效通读至检测限。该研究为后期构建新型硒蛋白及其乳酸菌细胞工厂奠定了基础。

关键词: 乳酸菌;乳酸乳球菌;谷胱甘肽过氧化物酶;突变体;重组表达

Abstract: We aimed to investigate the expression of selenocysteine (Sec)-containing selenoproteins in natural Lactococcus lactis and to analyze the differences in glutathione peroxidase (GPx) activity among the recombinant L. lactis NZ9000/pNZ8148-GPx (NG1) and mutants specifically producing selenoproteins generated by introducing the stop codon UGA (encoding Sec) and the cis-acting selenocysteine insertion sequence (SECIS) into the three cysteine sites (C36, C63 and C81) and the penultimate lysine site (L156) of LlGPx (the glutathione peroxidase expressed by NG1) under non-induced conditions, under nisin induction and under Se-enriched conditions. The results showed that under Se-enriched conditions, the activity of LlGPx (89.10 mU/mg) was comparable to that of the mutants (56.17–84.45 mU/mg). NG1 showed a band of 17.8 kDa on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), while none of the mutants showed complete or truncated bands corresponding to selenoproteins. This suggested that introduction of UGA and SECIS alone was insufficient for efficient read-through to detectable levels in L. lactis NZ9000 under the experimental conditions. This study lays a foundation for the construction of novel selenoproteins and their production in lactic acid bacterial cell factories.

Key words: lactic acid bacteria; Lactococcus lactis; glutathione peroxidase; mutant; recombinant expression

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