食品科学 ›› 2018, Vol. 39 ›› Issue (4): 76-81.doi: 10.7506/spkx1002-6630-201804012

• 生物工程 • 上一篇    下一篇

嗜酸乳杆菌ATCC4356分选酶A基因克隆、表达及功能分析

吴京1,王文文1,熊蓉露1,吴振1,*,潘道东1,2,*,曾小群1,郭宇星2   

  1. (1.宁波大学 浙江省动物蛋白食品精深加工技术重点实验室,浙江宁波 315211;2.南京师范大学金陵女子学院,江苏南京 210097)
  • 出版日期:2018-02-25 发布日期:2018-02-02
  • 基金资助:
    国家自然科学基金面上项目(31671869;31471598);国家自然科学基金青年科学基金项目(31671487);浙江省自然科学基金青年基金项目(LQ16C200002);宁波市科技富民项目(2016C10022)

Cloning, Expression and Characterization of Sortase A from Lactobacillus acidophilus ATCC4356

WU Jing1, WANG Wenwen1, XIONG Ronglu1, WU Zhen1,*, PAN Daodong1,2,*, ZENG Xiaoqun1, GUO Yuxing2   

  1. (1. Key Laboratory of Animal Protein Food Deep Processing Technology of Zhejiang Province, Ningbo University, Ningbo 315211, China; 2. Jinling College, Nanjing Normal University, Nanjing 210097, China)
  • Online:2018-02-25 Published:2018-02-02

摘要: 分选酶在细菌对宿主细胞的黏附过程中具有重要作用。为探究乳酸菌分选酶的特性及与其他致病菌分选酶的差异,以嗜酸乳杆菌ATCC4356为模板,构建分选酶A(sortase A,SrtA)重组表达载体pET28a-SrtAΔN48,转入大肠杆菌感受态细胞Transetta(DE3)内表达,使用Dabcyl-QALPTTGEE(Edans)探究其酶活特性。结果发现:嗜酸乳杆菌ATCC4356 SrtA(Lap-SrtAΔN48)分子质量为20kDa左右;Mg2+、Zn2+、Mn2+可提高Lap-SrtAΔN48的转肽能力;Ca2+不会影响SrtAΔN48的活性,明显区别于致病菌;且分选酶抑制剂查尔酮会抑制Lap-SrtAΔN48的活性。进一步通过蛋白质同源建模分析发现Lap-SrtA由8条中心β桶状结构互相折叠而成,属于经典的分选酶结构,Lap-SrtA的活性位点为His137、Cys198、Arg205。

关键词: 嗜酸乳杆菌, 分选酶A, 基因克隆, 酶学特性, 结构特性

Abstract: Sortase (Srt) plays an important role in the adhesion of Gram-positive bacteria to host cells. The focus of this study was to recombine the sortase A (SrtA) of Lactobacillus acidophilus (Lap-SrtA) in E. coli and to evaluate the differences between Lap-SrtA with other pathogenic sortase. The srtA gene was cloned from L. acidophilus ATCC4356 and expressed in E. coli Transetta (DE3). The recombinant protein was purified and analyzed using Dabcyl-QALPTTGEE (Edans) as substrate. The results showed that the molecular weight of the recombinant protein was about 20 kDa with an Lap-SrtA activity, and the activity could be enhanced by Mg2+, Zn2+, and Mn2+. However, Ca2+ had no visible effect on the activity of SrtA, making it distinct from other pathogenic sortase. Chalcone could significantly inhibit SrtA activity. Furthermore, there were eight segments of β sheet structure in Lap-SrtA as analyzed by homology modeling using SWISS MODEL, and the active site residues of Lap-SrtA were found to be His 137, Cys 198 and Arg 205.

Key words: Lactobacillus acidophilus, sortase A, cloning, enzyme activity, structural characterization

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