1N69

Crystal structure of human saposin B

Summary for 1N69

• Entry DOI: 10.2210/pdb1n69/pdb
• Descriptor: SAPOSIN B, 1,2-Distearoyl-sn-glycerophosphoethanolamine (3 entities in total)
• Functional Keywords: lipid binding protein, glycosphingolipid activator protein
• Biological source: Homo sapiens (human)
• Cellular location: Lysosome . Prosaposin: Secreted : P07602
• Total number of polymer chains: 3
• Total formula weight: 28133.65

Authors

Ahn, V.E.,Faull, K.F.,Whitelegge, J.P.,Fluharty, A.L.,Prive, G.G. (deposition date: 2002-11-08, release date: 2003-01-07, Last modification date: 2024-10-30)

Primary citation

Ahn, V.E.,Faull, K.F.,Whitelegge, J.P.,Fluharty, A.L.,Prive, G.G.
Crystal Structure of saposin B reveals a dimeric shell for lipid binding
Proc.Natl.Acad.Sci.USA, 100:38-43, 2003

PubMed Abstract: 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.

PubMed: 12518053
DOI: 10.1073/pnas.0136947100

Experimental method

X-RAY DIFFRACTION (2.2 Å)