9AVS
Human alpha-galactosidase A in complex with saposin B
Summary for 9AVS
| Entry DOI | 10.2210/pdb9avs/pdb |
| Related | 9AXG |
| Descriptor | Alpha-galactosidase A, Saposin-B, alpha-D-mannopyranose-(1-3)-beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose, ... (9 entities in total) |
| Functional Keywords | galactosidase, gla, saposin, sapb, fabry disease, lysosomal, hydrolase, activator protein |
| Biological source | Homo sapiens (human) More |
| Total number of polymer chains | 3 |
| Total formula weight | 108503.51 |
| Authors | Sawyer, T.K.,Garman, S.C. (deposition date: 2024-03-04, release date: 2024-04-17, Last modification date: 2024-10-23) |
| Primary citation | Sawyer, T.K.,Aral, E.,Staros, J.V.,Bobst, C.E.,Garman, S.C. Human Saposin B Ligand Binding and Presentation to alpha-Galactosidase A. Biorxiv, 2024 Cited by PubMed Abstract: Sphingolipid activator protein B (saposin B; SapB) is an essential activator of globotriaosylceramide (Gb3) catabolism by α-galactosidase A. However, the manner by which SapB stimulates α-galactosidase A activity remains unknown. To uncover the molecular mechanism of SapB presenting Gb3 to α-galactosidase A, we subjected the fluorescent substrate globotriaosylceramide-nitrobenzoxidazole (Gb3-NBD) to a series of biochemical and structural assays involving SapB. First, we showed that SapB stably binds Gb3-NBD using a fluorescence equilibrium binding assay, isolates Gb3-NBD from micelles, and facilitates α-galactosidase A cleavage of Gb3-NBD . Second, we crystallized SapB in the presence of Gb3-NBD and validated the ligand-bound assembly. Third, we captured transient interactions between SapB and α-galactosidase A by chemical cross-linking. Finally, we determined the crystal structure of SapB bound to α-galactosidase A. These findings establish general principles for molecular recognition in saposin:hydrolase complexes and highlight the utility of NBD reporter lipids in saposin biochemistry and structural biology. PubMed: 38617236DOI: 10.1101/2024.04.04.584535 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.53 Å) |
Structure validation
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