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Structural basis of aspartylglucosaminuria
Seiji Saito1, Kazuki Ohno, Kanako Sugawara
1Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan.
Biochemical and Biophysical Research Communications
|November 11, 2008
Summary
Structural modeling of aspartylglucosaminidase (AGA) reveals how mutations cause aspartylglucosaminuria (AGU). Different mutation groups show distinct structural changes, impacting enzyme function and folding.
Area of Science:
- Biochemistry
- Structural Biology
- Enzymology
Background:
- Aspartylglucosaminuria (AGU) is a lysosomal storage disease caused by mutations in the aspartylglucosaminidase (AGA) gene.
- Understanding the structural basis of AGA mutations is crucial for elucidating AGU pathogenesis.
Purpose of the Study:
- To investigate the structural consequences of AGU-associated mutations in the aspartylglucosaminidase (AGA) enzyme.
- To correlate structural changes with biochemical phenotypes of AGU.
Main Methods:
- Construction of structural models for mutant AGA proteins using molecular modeling software (TINKER).
- Classification of mutations into three groups based on biochemical phenotype.
- Calculation of solvent-accessible surface area (ASA), affected atoms, and root-mean-square deviation (RMSD) to quantify structural changes.
- Geographical and semi-quantitative analysis of structural alterations using atom coloring based on distance metrics.
Main Results:
- Group 1 mutations (folding/transport defects, complete activity loss) showed large structural changes in the enzyme core.
- Group 2 mutations (mature protein, no activity) significantly affected functionally important regions.
- Group 3 mutations (residual activity) exhibited small, surface-localized structural changes.
Conclusions:
- Structural modeling provides key insights into the molecular basis of aspartylglucosaminuria (AGU).
- The location and extent of structural changes in AGA correlate with enzyme activity and disease phenotype.
- This approach aids in understanding enzyme dysfunction in genetic disorders.
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