Related Experiment Video
Updated: Jul 13, 2026
09:01
Mutagenesis and Functional Selection Protocols for Directed Evolution of Proteins in E. coli
Published on: March 16, 2011
Maximization of dextransucrase activity expressed in E. coli by mutation and its functional characterization
Seung Hee Nam1, Eun Ah Ko, Suk Sang Jang
1Jeonnam Agricultural Research & Extension Services, Jeonnam, Naju 520-715, Korea.
Biotechnology Letters
|August 4, 2007
Summary
A new dextransucrase gene (DSRN) was created and mutated, enhancing its enzymatic properties. DSRN3 showed the highest transglycosylation efficiency, making it a promising enzyme for industrial applications.
Area of Science:
- Enzymology
- Protein Engineering
- Biotechnology
Background:
- Dextransucrases are enzymes that synthesize dextran from sucrose.
- Improving dextransucrase activity and efficiency is crucial for industrial applications.
- Gene modification techniques offer a pathway to enhance enzyme performance.
Purpose of the Study:
- To generate a novel dextransucrase gene (DSRN) with improved properties.
- To create and characterize mutants of the DSRN gene.
- To evaluate the enzymatic activity and transglycosylation efficiency of the engineered dextransucrases.
Main Methods:
- Ultrasoft X-ray treatment was used to obtain the novel DSRN gene from the DSRB742 gene.
- Site-directed mutagenesis was employed to create four DSRN mutants (DSRN1-4).
- Recombinant expression in E. coli, affinity purification using dextran, and enzymatic assays were performed.
Main Results:
- The DSRN gene was successfully generated and mutated, yielding four variants.
- Purified dextransucrases exhibited specific activities ranging from 0.6-17 U/mg.
- DSRN1 showed the highest catalytic efficiency (Kcat/Km), while DSRN3 demonstrated superior transglycosylation efficiency with various substrates.
Conclusions:
- Novel dextransucrase variants with enhanced enzymatic properties were successfully engineered.
- DSRN3 exhibits significant potential for applications requiring high transglycosylation efficiency.
- This study provides a foundation for further optimization of dextransucrases for biotechnological uses.
