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Updated: May 27, 2026
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Purification of a High Molecular Mass Protein in Streptococcus mutans
Published on: September 14, 2019
Crystallization and preliminary crystallographic analysis of dextranase from Streptococcus mutans
Nobuhiro Suzuki1, Young Min Kim, Zui Fujimoto
1Biomolecular Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
Summary
This study details the crystallization of Streptococcus mutans dextranase, an enzyme crucial for breaking down dextran. The resulting crystals allowed for high-resolution structural analysis, advancing our understanding of glycoside hydrolase family 66.
Area of Science:
- Biochemistry
- Structural Biology
- Enzymology
Background:
- Streptococcus mutans dextranase is a key enzyme in glycoside hydrolase family 66.
- It specifically hydrolyzes internal α-1,6-linkages within dextran molecules.
Purpose of the Study:
- To obtain high-resolution crystals of a modified Streptococcus mutans dextranase.
- To facilitate structural determination of the enzyme for further functional studies.
Main Methods:
- A modified Streptococcus mutans dextranase, with N- and C-terminal deletions, was used.
- Crystallization was achieved using the sitting-drop vapor-diffusion method.
- X-ray diffraction data was collected to a resolution of 1.6 Å.
Main Results:
- The crystals belonged to the monoclinic space group P2(1).
- Unit-cell parameters were determined as a = 53.2 Å, b = 89.7 Å, c = 63.3 Å, with β = 102.3°.
- The Matthews coefficient suggested either one or two molecules per asymmetric unit.
Conclusions:
- Successful crystallization of the S. mutans dextranase mutant provides a foundation for detailed structural analysis.
- This structural information can elucidate the enzyme's catalytic mechanism and substrate specificity.
- Further studies can leverage these findings for potential biotechnological applications.
