2HAZ

Crystal structure of the first fibronectin domain of human NCAM1

Summary for 2HAZ

• Entry DOI: 10.2210/pdb2haz/pdb
• Descriptor: Neural cell adhesion molecule 1, SODIUM ION (3 entities in total)
• Functional Keywords: fibronectin type iii repeat, fn1, ncam, beta sandwich, cell adhesion
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 1
• Total formula weight: 11388.61

Authors

Sekulic, N.,Lavie, A. (deposition date: 2006-06-13, release date: 2006-10-03, Last modification date: 2023-08-30)

Primary citation

Mendiratta, S.S.,Sekulic, N.,Hernandez-Guzman, F.G.,Close, B.E.,Lavie, A.,Colley, K.J.
A novel alpha-helix in the first fibronectin type III repeat of the neural cell adhesion molecule is critical for N-glycan polysialylation.
J.Biol.Chem., 281:36052-36059, 2006

PubMed Abstract: 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.

PubMed: 17003032
DOI: 10.1074/jbc.M608073200

Experimental method

X-RAY DIFFRACTION (1.7 Å)