Maximization of dextransucrase activity expressed in E-coli by mutation and its functional characterization

被引：6

作者：

Nam, Seung Hee

Ko, Eun Ah

Jang, Suk Sang

Kim, Do Won

Kim, Se Yong

Hwang, Dae Sung

Kim, Doman ^{[1
]}

机构：

[1] Jeonnam Natl Univ, Sch Biol Sci & Technol, Kwangju 500757, South Korea

[2] Jeonnam Natl Univ, Res Inst Catalysis, Kwangju 500757, South Korea

[3] Jeonnam Agr Res & Extens Serv, Naju 520715, South Korea

[4] Pohang Accelerator Lab, Pohang 790784, South Korea

[5] Kangnung Natl Univ, Dept Phys, Kangnung 210702, South Korea

[6] Sejong Univ, Dept Phys, Seoul 143747, South Korea

来源：

BIOTECHNOLOGY LETTERS | 2008年 / 30卷 / 01期

关键词：

acceptor reaction; dextransucrase; Leuconostoc mesenteroides; mutation; Ultrasoft X-ray;

D O I：

10.1007/s10529-007-9498-z

中图分类号：

Q81 [生物工程学（生物技术）]; Q93 [微生物学];

学科分类号：

071005 ; 0836 ; 090102 ; 100705 ;

摘要：

A novel dextransucrase gene, DSRN, was obtained by ultrasoft X-ray treatment of the DSRB742 gene. The DSRN gene was further mutated via site-directed mutagenesis producing four mutants: DSRN1 (F196S), DSRN2 (Y346N), DSRN3 (K395T) and DSRN4 (P980T). Dextransucrases derived from DSRB742 and its mutants were expressed in E. coli and affinity-purified using dextran to give 80% purity. They had specific activities of 0.6-17 U/mg with Km values of 18-88 mM. DSRB742 had the lowest (0.02 s(-1) center dot mM(-1)) and DSRN1 had the highest (0.13 s(-1) center dot mM(-1)) Kcat/Km values. DSRN3 had the highest enzymatic transglycosylation efficiency with maltose (63% of theoretical), gentiobiose (39%), or salicine (40%).

引用

页码：135 / 143

页数：9

共 24 条

[1] Proteolytic modification of Leuconostoc mesenteroides B-512F dextransucrase [J].