2dob | pdb_00002dob
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| 2dob, resolution 2.00Å | |||||||||||||
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| Ligands: | CA | ||||||||||||
| Gene: | PSAP (Homo sapiens) | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Crystal Structure of Human Saposin A
Overview
Saposins A and C are sphingolipid activator proteins required for the lysosomal breakdown of galactosylceramide and glucosylceramide, respectively. The saposins interact with lipids, leading to an enhanced accessibility of the lipid headgroups to their cognate hydrolases. We have determined the crystal structures of human saposins A and C to 2.0 Angstroms and 2.4 Angstroms, respectively, and both reveal the compact, monomeric saposin fold. We confirmed that these two proteins were monomeric in solution at pH 7.0 by analytical centrifugation. However, at pH 4.8, in the presence of the detergent C(8)E(5), saposin A assembled into dimers, while saposin C formed trimers. Saposin B was dimeric under all conditions tested. The self-association of the saposins is likely to be relevant to how these small proteins interact with lipids, membranes, and hydrolase enzymes.
Disease
Known diseases associated with this structure: Combined SAP deficiency OMIM:[176801], Gaucher disease, atypical OMIM:[176801], Krabbe disease, atypical OMIM:[176801], Metachromatic leukodystrophy due to SAP-b deficiency OMIM:[176801]
About this Structure
2DOB is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Crystal structures of saposins A and C., Ahn VE, Leyko P, Alattia JR, Chen L, Prive GG, Protein Sci. 2006 Aug;15(8):1849-57. Epub 2006 Jul 5. PMID:16823039
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