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1g13
From Proteopedia
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[[Image:1g13.gif|left|200px]] | [[Image:1g13.gif|left|200px]] | ||
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'''HUMAN GM2 ACTIVATOR STRUCTURE''' | '''HUMAN GM2 ACTIVATOR STRUCTURE''' | ||
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[[Category: Rastinejad, F.]] | [[Category: Rastinejad, F.]] | ||
[[Category: Wright, C S.]] | [[Category: Wright, C S.]] | ||
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Revision as of 14:00, 2 May 2008
HUMAN GM2 ACTIVATOR STRUCTURE
Overview
GM2 activator protein (GM2-AP) belongs to a small group of non- enzymatic lysosomal proteins that act as cofactors in the sequential degradation of gangliosides. It has been postulated that GM2-AP extracts single GM2 molecules from membranes and presents them in soluble form to beta-hexosaminidase A for cleavage of N-acetyl-d-galactosamine and conversion to GM3. The high affinity of GM2-AP for GM2 is based on specfic recognition of the oligosaccharide moiety as well as the ceramide lipid tail. Genetic defects in GM2-AP result in an atypical form of Tay-Sachs disease known as variant AB GM2 gangliosidosis. The 2.0 A resolution crystal structure of GM2-AP reported here reveals a previously unobserved fold whose main feature is an eight-stranded cup-shaped anti-parallel beta-pleated sheet. The striking feature of the GM2-AP structure is that it possesses an accessible central hydrophobic cavity rather than a buried hydrophobic core. The dimensions of this cavity (12 Ax14 Ax22 A) are suitable for binding 18-carbon lipid acyl chains. Flexible surface loops and a short alpha-helix decorate the mouth of the beta-cup and may control lipid entry to the cavity.
About this Structure
1G13 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Crystal structure of human GM2-activator protein with a novel beta-cup topology., Wright CS, Li SC, Rastinejad F, J Mol Biol. 2000 Dec 1;304(3):411-22. PMID:11090283 Page seeded by OCA on Fri May 2 16:59:59 2008
