1n69
Crystal structure of human saposin B
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OverviewOverview
Saposin B is a small, nonenzymatic glycosphingolipid activator protein required for the breakdown of cerebroside sulfates (sulfatides) within the lysosome. The protein can extract target lipids from membranes, forming soluble protein-lipid complexes that are recognized by arylsulfatase A. The crystal structure of human saposin B reveals an unusual shell-like dimer consisting of a monolayer of alpha-helices enclosing a large hydrophobic cavity. Although the secondary structure of saposin B is similar to that of the known monomeric members of the saposin-like superfamily, the helices are repacked into a different tertiary arrangement to form the homodimer. A comparison of the two forms of the saposin B dimer suggests that extraction of target lipids from membranes involves a conformational change that facilitates access to the inner cavity.
DiseaseDisease
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 StructureAbout this Structure
1N69 is a Single protein structure of sequence from Homo sapiens with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of saposin B reveals a dimeric shell for lipid binding., Ahn VE, Faull KF, Whitelegge JP, Fluharty AL, Prive GG, Proc Natl Acad Sci U S A. 2003 Jan 7;100(1):38-43. Epub 2002 Dec 23. PMID:12518053
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