The X-Ray Crystal Structure of Human Beta-Hexosaminidase B Provides New Insights Into Sandhoff DiseaseMaier, T., Strater, N., Schuette, C., Klingenstein, R., Sandhoff, K., Saenger, W.
(2003) J.Mol.Biol. 328: 669
- PubMed: 12706724
- PubMed Abstract:
- Complete Analysis of the Glycosylation and Disulfide Bond Pattern of Human Beta-Hexosaminidase B by Maldi-Ms
Schuette, C.G.,Weissgerber, J.,Sandhoff, K.
(2001) Glycobiology 11: 549
- Synthesis of a Huamn Lysosomal Enzyme, Beta-Hexosaminidase B, Using the Baculaovirus Expression System
Boose, J.A.,Tifft, C.J.,Proia, R.L.,Myerowitz, R.
(1990) Protein Expr.Purif. 1: 111
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 hexos ...
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.
Institut für Chemie Kristallographie, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany.