Structure of sulfamidase provides insight into the molecular pathology of mucopolysaccharidosis IIIA
- University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen (Germany)
- University of Göttingen, Tammannstrasse 4, 37077 Göttingen (Germany)
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen (Germany)
- Instituto de Biologia Molecular de Barcelona (IBMB–CSIC), Barcelona Science Park, Baldiri Reixach 15, 08028 Barcelona (Spain)
Mucopolysaccharidosis IIIA is a fatal neurodegenerative disease that typically manifests itself in childhood and is caused by mutations in the gene for the lysosomal enzyme sulfamidase. The first structure of this enzyme is presented, which provides insight into the molecular basis of disease-causing mutations, and the enzymatic mechanism is proposed. Mucopolysaccharidosis type IIIA (Sanfilippo A syndrome), a fatal childhood-onset neurodegenerative disease with mild facial, visceral and skeletal abnormalities, is caused by an inherited deficiency of the enzyme N-sulfoglucosamine sulfohydrolase (SGSH; sulfamidase). More than 100 mutations in the SGSH gene have been found to reduce or eliminate its enzymatic activity. However, the molecular understanding of the effect of these mutations has been confined by a lack of structural data for this enzyme. Here, the crystal structure of glycosylated SGSH is presented at 2 Å resolution. Despite the low sequence identity between this unique N-sulfatase and the group of O-sulfatases, they share a similar overall fold and active-site architecture, including a catalytic formylglycine, a divalent metal-binding site and a sulfate-binding site. However, a highly conserved lysine in O-sulfatases is replaced in SGSH by an arginine (Arg282) that is positioned to bind the N-linked sulfate substrate. The structure also provides insight into the diverse effects of pathogenic mutations on SGSH function in mucopolysaccharidosis type IIIA and convincing evidence for the molecular consequences of many missense mutations. Further, the molecular characterization of SGSH mutations will lay the groundwork for the development of structure-based drug design for this devastating neurodegenerative disorder.
- OSTI ID:
- 22347798
- Journal Information:
- Acta Crystallographica. Section D: Biological Crystallography, Vol. 70, Issue Pt 5; Other Information: PMCID: PMC4014121; PMID: 24816101; PUBLISHER-ID: cb5050; OAI: oai:pubmedcentral.nih.gov:4014121; Copyright (c) Sidhu et al. 2014; This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0907-4449
- Country of Publication:
- Denmark
- Language:
- English
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