2haz
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(New page: 200px<br /> <applet load="2haz" size="450" color="white" frame="true" align="right" spinBox="true" caption="2haz, resolution 1.700Å" /> '''Crystal structure ...)
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Revision as of 20:22, 12 November 2007
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Crystal structure of the first fibronectin domain of human NCAM1
Overview
Polysialic acid is a developmentally regulated, anti-adhesive glycan that, is added to the neural cell adhesion molecule, NCAM. Polysialylated NCAM, is critical for brain development and plays roles in synaptic plasticity, axon guidance, and cell migration. The first fibronectin type III repeat, of NCAM, FN1, is necessary for the polysialylation of N-glycans on the, adjacent immunoglobulin domain. This repeat cannot be replaced by other, fibronectin type III repeats. We solved the crystal structure of human, NCAM FN1 and found that, in addition to a unique acidic surface patch, it, possesses a novel alpha-helix that links strands 4 and 5 of its, beta-sandwich structure. Replacement of the alpha-helix did not eliminate, polysialyltransferase recognition, but shifted the addition of polysialic, acid from the N-glycans modifying the adjacent immunoglobulin domain to, O-glycans modifying FN1. Other experiments demonstrated that replacement, of residues in the acidic surface patch alter the polysialylation of both, N- and O-glycans in the same way, while the alpha-helix is only required, for the polysialylation of N-glycans. Our data are consistent with a model, in which the FN1 alpha-helix is involved in an Ig5-FN1 interaction that is, critical for the correct positioning of Ig5 N-glycans for polysialylation.
About this Structure
2HAZ is a Single protein structure of sequence from Homo sapiens with NA as ligand. Full crystallographic information is available from OCA.
Reference
A novel alpha-helix in the first fibronectin type III repeat of the neural cell adhesion molecule is critical for N-glycan polysialylation., Mendiratta SS, Sekulic N, Hernandez-Guzman FG, Close BE, Lavie A, Colley KJ, J Biol Chem. 2006 Nov 24;281(47):36052-9. Epub 2006 Sep 26. PMID:17003032
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