4fdi

The molecular basis of mucopolysaccharidosis IV A

spinqualitylabelsall models 4fdi, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4fdi is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Ligands: CA, CIT, DDZ, GOL, NAG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease GALNS_HUMAN Mucopolysaccharidosis type 4A. The disease is caused by mutations affecting the gene represented in this entry. Function GALNS_HUMAN Publication Abstract from PubMed Lysosomal enzymes catalyze the breakdown of macromolecules in the cell. In humans, loss of activity of a lysosomal enzyme leads to an inherited metabolic defect known as a lysosomal storage disorder. The human lysosomal enzyme galactosamine-6-sulfatase (GALNS, also known as N-acetylgalactosamine-6-sulfatase and GalN6S; E.C. 3.1.6.4) is deficient in patients with the lysosomal storage disease mucopolysaccharidosis IV A (also known as MPS IV A and Morquio A). Here, we report the three-dimensional structure of human GALNS, determined by X-ray crystallography at 2.2A resolution. The structure reveals a catalytic gem diol nucleophile derived from modification of a cysteine side chain. The active site of GALNS is a large, positively charged trench suitable for binding polyanionic substrates such as keratan sulfate and chondroitin-6-sulfate. Enzymatic assays on the insect-cell-expressed human GALNS indicate activity against synthetic substrates and inhibition by both substrate and product. Mapping 120 MPS IV A missense mutations onto the structure reveals that a majority of mutations affect the hydrophobic core of the structure, indicating that most MPS IV A cases result from misfolding of GALNS. Comparison of the structure of GALNS to paralogous sulfatases shows a wide variety of active-site geometries in the family but strict conservation of the catalytic machinery. Overall, the structure and the known mutations establish the molecular basis for MPS IV A and for the larger MPS family of diseases. The Structure of Human GALNS Reveals the Molecular Basis for Mucopolysaccharidosis IV A.,Rivera-Colon Y, Schutsky EK, Kita AZ, Garman SC J Mol Biol. 2012 Aug 29. PMID:22940367 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Sulfatase 3D structures

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