1E33

Crystal structure of an Arylsulfatase A mutant P426L

Summary for 1E33

• Entry DOI: 10.2210/pdb1e33/pdb
• Related: 1AUK 1E2S 1E3C
• Descriptor: Arylsulfatase A, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: hydrolase, cerebroside-3-sulfate hydrolysis, lysosomal enzyme, formylglycine
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 1
• Total formula weight: 52424.48

Authors

von Buelow, R.,Schmidt, B.,Dierks, T.,von Figura, K.,Uson, I. (deposition date: 2000-06-06, release date: 2001-05-25, Last modification date: 2024-11-20)

Primary citation

von Bulow, R.,Schmidt, B.,Dierks, T.,Schwabauer, N.,Schilling, K.,Weber, E.,Uson, I.,von Figura, K.
Defective oligomerization of arylsulfatase a as a cause of its instability in lysosomes and metachromatic leukodystrophy.
J. Biol. Chem., 277:9455-9461, 2002

PubMed Abstract: In one of the most common mutations causing metachromatic leukodystrophy, the P426L-allele of arylsulfatase A (ASA), the deficiency of ASA results from its instability in lysosomes. Inhibition of lysosomal cysteine proteinases protects the P426L-ASA and restores the sulfatide catabolism in fibroblasts of the patients. P426L-ASA, but not wild type ASA, was cleaved by purified cathepsin L at threonine 421 yielding 54- and 9-kDa fragments. X-ray crystallography at 2.5-A resolution showed that cleavage is not due to a difference in the protein fold that would expose the peptide bond following threonine 421 to proteases. Octamerization, which depends on protonation of Glu-424, was impaired for P426L-ASA. The mutation lowers the pH for the octamer/dimer equilibrium by 0.6 pH units from pH 5.8 to 5.2. A second oligomerization mutant (ASA-A464R) was generated that failed to octamerize even at pH 4.8. A464R-ASA was degraded in lysosomes to catalytically active 54-kDa intermediate. In cathepsin L-deficient fibroblasts, degradation of P426L-ASA and A464R-ASA to the 54-kDa fragment was reduced, while further degradation was blocked. This indicates that defective oligomerization of ASA allows degradation of ASA to a catalytically active 54-kDa intermediate by lysosomal cysteine proteinases, including cathepsin L. Further degradation of the 54-kDa intermediate critically depends on cathepsin L and is modified by the structure of the 9-kDa cleavage product.

PubMed: 11777924
DOI: 10.1074/jbc.M111993200

Experimental method

X-RAY DIFFRACTION (2.5 Å)