1o7a
From Proteopedia
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'''HUMAN BETA-HEXOSAMINIDASE B''' | '''HUMAN BETA-HEXOSAMINIDASE B''' | ||
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[[Category: Schuette, C.]] | [[Category: Schuette, C.]] | ||
[[Category: Strater, N.]] | [[Category: Strater, N.]] | ||
| - | [[Category: | + | [[Category: Ba8-barrel]] |
| - | [[Category: | + | [[Category: Glycosidase]] |
| - | [[Category: | + | [[Category: Glycosyl hydrolase]] |
| - | [[Category: | + | [[Category: Hexosaminidase]] |
| - | [[Category: | + | [[Category: Lysosomal]] |
| - | [[Category: | + | [[Category: Sandhoff disease]] |
| - | [[Category: | + | [[Category: Sphingolipid degradation]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 03:28:22 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 00:28, 3 May 2008
HUMAN BETA-HEXOSAMINIDASE B
Overview
Human lysosomal beta-hexosaminidases are dimeric enzymes composed of alpha and beta-chains, encoded by the genes HEXA and HEXB. They occur in three isoforms, the homodimeric hexosaminidases B (betabeta) and S (alphaalpha), and the heterodimeric hexosaminidase A (alphabeta), where dimerization is required for catalytic activity. Allelic variations in the HEXA and HEXB genes cause the fatal inborn errors of metabolism Tay-Sachs disease and Sandhoff disease, respectively. Here, we present the crystal structure of a complex of human beta-hexosaminidase B with a transition state analogue inhibitor at 2.3A resolution (pdb 1o7a). On the basis of this structure and previous studies on related enzymes, a retaining double-displacement mechanism for glycosyl hydrolysis by beta-hexosaminidase B is proposed. In the dimer structure, which is derived from an analysis of crystal packing, most of the mutations causing late-onset Sandhoff disease reside near the dimer interface and are proposed to interfere with correct dimer formation. The structure reported here is a valid template also for the dimeric structures of beta-hexosaminidase A and S.
About this Structure
1O7A is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
The X-ray crystal structure of human beta-hexosaminidase B provides new insights into Sandhoff disease., Maier T, Strater N, Schuette CG, Klingenstein R, Sandhoff K, Saenger W, J Mol Biol. 2003 May 2;328(3):669-81. PMID:12706724 Page seeded by OCA on Sat May 3 03:28:22 2008
