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Structural Characterization of Mannan Cell Wall Polysaccharides in Plants Using PACE
Published on: October 16, 2017
Characterization of carrot pectin methylesterase
O Markovic1, E Cederlund, W J Griffiths
1Institute of Chemistry, Slovak Academy of Sciences, Bratislava.
Cellular and Molecular Life Sciences : CMLS
|April 20, 2002
Summary
Researchers purified alkaline pectin methylesterase from carrots, revealing its 319-residue structure and N-terminal pyroglutamyl group. This structural insight aids in understanding enzyme relationships and conserved functional residues.
Area of Science:
- Biochemistry
- Enzymology
- Structural Biology
Background:
- Pectin methylesterase (PME) enzymes modify plant cell walls.
- Understanding PME structure is crucial for its function and classification.
- Limited structural data exists for diverse PME forms.
Purpose of the Study:
- Purify and structurally analyze the most alkaline PME from carrot roots.
- Determine the primary and three-dimensional structure of the mature enzyme.
- Compare the carrot PME structure with other known forms to identify relationships.
Main Methods:
- Enzyme purification from ripe carrot roots.
- N-terminal blocking group analysis.
- Primary structure determination.
- Crystallographic analysis for 3D structure.
- Bioinformatic comparison with GenBank data.
Main Results:
- Isolated and purified the most alkaline PME from carrot roots.
- Determined the mature enzyme comprises 319 residues.
- Identified the N-terminal blocking group as a pyroglutamyl residue.
- Obtained the three-dimensional structure, adding to the limited existing data.
- Compared 39 PME forms, revealing conserved Asp residues at positions 136 and 157.
Conclusions:
- The determined carrot PME structure provides valuable insights into enzyme family relationships.
- Conserved aspartic acid residues are likely critical for PME function across different forms.
- This study contributes to the structural understanding of pectin methylesterases.
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