1e33
From Proteopedia
(New page: 200px<br /> <applet load="1e33" size="450" color="white" frame="true" align="right" spinBox="true" caption="1e33, resolution 2.50Å" /> '''CRYSTAL STRUCTURE O...) |
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| - | [[Image:1e33.gif|left|200px]]<br /> | + | [[Image:1e33.gif|left|200px]]<br /><applet load="1e33" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1e33" size=" | + | |
caption="1e33, resolution 2.50Å" /> | caption="1e33, resolution 2.50Å" /> | ||
'''CRYSTAL STRUCTURE OF AN ARYLSULFATASE A MUTANT P426L'''<br /> | '''CRYSTAL STRUCTURE OF AN ARYLSULFATASE A MUTANT P426L'''<br /> | ||
==Overview== | ==Overview== | ||
| - | In one of the most common mutations causing metachromatic leukodystrophy, the P426L-allele of arylsulfatase A (ASA), the deficiency of ASA results | + | 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. |
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1E33 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with MG as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cerebroside-sulfatase Cerebroside-sulfatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.6.8 3.1.6.8] Full crystallographic information is available from [http:// | + | 1E33 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cerebroside-sulfatase Cerebroside-sulfatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.6.8 3.1.6.8] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1E33 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Buelow, R | + | [[Category: Buelow, R Von.]] |
[[Category: Dierks, T.]] | [[Category: Dierks, T.]] | ||
| - | [[Category: Figura, K | + | [[Category: Figura, K Von.]] |
[[Category: Schmidt, B.]] | [[Category: Schmidt, B.]] | ||
[[Category: Uson, I.]] | [[Category: Uson, I.]] | ||
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[[Category: lysosomal enzyme]] | [[Category: lysosomal enzyme]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:23:15 2008'' |
Revision as of 10:23, 21 February 2008
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CRYSTAL STRUCTURE OF AN ARYLSULFATASE A MUTANT P426L
Contents |
Overview
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.
Disease
Known disease associated with this structure: Metachromatic leukodystrophy OMIM:[607574]
About this Structure
1E33 is a Single protein structure of sequence from Homo sapiens with as ligand. Active as Cerebroside-sulfatase, with EC number 3.1.6.8 Full crystallographic information is available from OCA.
Reference
Defective oligomerization of arylsulfatase a as a cause of its instability in lysosomes and metachromatic leukodystrophy., von Bulow R, Schmidt B, Dierks T, Schwabauer N, Schilling K, Weber E, Uson I, von Figura K, J Biol Chem. 2002 Mar 15;277(11):9455-61. Epub 2002 Jan 2. PMID:11777924
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