生物技术通报 ›› 2020, Vol. 36 ›› Issue (12): 82-90.doi: 10.13560/j.cnki.biotech.bull.1985.2020-0375

• 研究报告 • 上一篇    下一篇

Mangrovibacterium sp. SH-52耐热内切型海藻酸裂解酶基因的克隆及酶学鉴定

李卫娜1(), 申冬玲2, 张煜星1, 刘学通1, 伊日布斯2()   

  1. 1.西京学院医学院,西安 710000
    2.昆明理工大学生命科学与技术学院,昆明 650500
  • 收稿日期:2020-04-06 出版日期:2020-12-26 发布日期:2020-12-22
  • 作者简介:李卫娜,女,硕士研究生,研究方向:微生物学;E-mail:liweina502361483@163.com
  • 基金资助:
    西京学院校科研基金(XJ180214)

Cloning and Enzymatic Identification of Thermo-tolerant and Endotype Alginate Lyase Gene from Mangrovibacterium sp. SH-52

LI Wei-na1(), SHEN Dong-ling2, ZHANG Yu-xing1, LIU Xue-tong1, IRBIS Chagan2()   

  1. 1. School of Medicine,Xijing University,Xi’an 710000;
    2. Faculty of Life Science and Technology,Kunming University of Science and Technology,Kunming 650500
  • Received:2020-04-06 Published:2020-12-26 Online:2020-12-22

摘要:

研究来自厌氧海藻酸分解菌的海藻酸裂解酶,表征其酶学特征,旨为丰富海藻酸裂解酶工业应用提供理论依据。从一株厌氧菌Mangrovibacterium sp. SH-52中克隆一个海藻酸裂解酶基因SHA-I,分析基因序列,并在大肠杆菌中进行异源表达,纯化后对其酶学性质进行分析。SHA-I由362个氨基酸构成,分子量大约为41 kD,与Lewinella cohaerens中的海藻酸裂解酶同源性最高,为80%,属于多聚糖裂解酶类(Polysaccharide lyase,PL)7家族。SHA-I最适pH为7.0,最适温度是50℃,在60℃时的活性超过最高活性的50%,在80℃时约为最高活性的40%,表明SHA-I是一种耐热性海藻酸裂解酶。SHA-I对polyG(聚甘露糖醛酸)有底物特异性,其降解海藻酸主要产生二糖和三糖,是一种内切型海藻酸裂解酶。

关键词: 厌氧海藻酸分解菌, Mangrovibacterium sp. SH-52, 异源表达, 内切型海藻酸裂解酶, 耐热性

Abstract:

The objective of this work is to investigate the alginate lyases isolated from anaerobic alginolytic bacteria,to characterize the novel alginate lyase,thus to provide a theoretical basis for the enriching industrial application of alginate lyase. A gene SHA-I encoding an alginate lyase was cloned from an anaerobic bacterium Mangrovibacterium sp. SH-52,sequenced and expressed in Escherichia coli. Its expressed enzyme was purified and the enzymatic characteristics were analyzed. The alginate lyase SHA-I was composed of 362 amino acids with molecular weight of approximately 41 kD. SHA-I belonged to polysaccharide lyase(PL)family 7 and showed 83% amino acid identity with alginate lyase from Lewinella agarilytica. The optimal pH for SHA-I activity was 7.0. SHA-I demonstrated the highest activity at 50℃and remained approximate 60% of the highest activity at 60℃,and 40% at 80℃,indicating that SHA-I was a thermo-tolerant alginate lyase. SHA-I presented substrate specificity to polyG(polymannuronic acid). It degraded polyG blocks to alginate oligosaccharides as the main products.

Key words: anaerobic alginolytic bacteria, Mangrovibacterium sp. SH-52, heterologous expression, endotype alginate lyase, thermo-tolerant