The characterization of modified starch branching enzymes: toward the control of starch chain-length distributions
| Autor: | Alan E. Mark, Cheng Li, Mark S. Turner, Alpeshkumar K. Malde, Alex Wu, Rob Marc Go, Jacob Malouf, Robert G. Gilbert |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Starch
Mutant Molecular Sequence Data lcsh:Medicine Gene Expression Molecular Dynamics Simulation Branching (polymer chemistry) Protein Engineering Zea mays Modified starch chemistry.chemical_compound Structure-Activity Relationship 1 4-alpha-Glucan Branching Enzyme Escherichia coli Cloning Molecular lcsh:Science Glucan Enzyme Assays Plant Proteins chemistry.chemical_classification Multidisciplinary biology lcsh:R food and beverages Enzyme assay Enzyme structure Recombinant Proteins Molecular Weight Enzyme chemistry Biochemistry Amino Acid Substitution Carbohydrate Sequence Mutation biology.protein Chromatography Gel Mutagenesis Site-Directed lcsh:Q Research Article |
| Zdroj: | PLoS ONE PLoS ONE, Vol 10, Iss 4, p e0125507 (2015) |
| ISSN: | 1932-6203 |
| Popis: | Starch is a complex branched glucose polymer whose branch molecular weight distribution (the chain-length distribution, CLD) influences nutritionally important properties such as digestion rate. Chain-stopping in starch biosynthesis is by starch branching enzyme (SBE). Site-directed mutagenesis was used to modify SBEIIa from Zea mays (mSBEIIa) to produce mutants, each differing in a single conserved amino-acid residue. Products at different times from in vitro branching were debranched and the time evolution of the CLD measured by size-exclusion chromatography. The results confirm that Tyr352, Glu513, and Ser349 are important for mSBEIIa activity while Arg456 is important for determining the position at which the linear glucan is cut. The mutant mSBEIIa enzymes have different activities and suggest the length of the transferred chain can be varied by mutation. The work shows analysis of the molecular weight distribution can yield information regarding the enzyme branching sites useful for development of plants yielding starch with improved functionality. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|