2v5m
|
STRUCTURAL BASIS FOR DSCAM ISOFORM SPECIFICITY
OverviewOverview
The Dscam gene gives rise to thousands of diverse cell surface receptors, thought to provide homophilic and heterophilic recognition specificity for, neuronal wiring and immune responses. Mutually exclusive splicing allows, for the generation of sequence variability in three immunoglobulin, ecto-domains, D2, D3 and D7. We report X-ray structures of the, amino-terminal four immunoglobulin domains (D1-D4) of two distinct Dscam, isoforms. The structures reveal a horseshoe configuration, with variable, residues of D2 and D3 constituting two independent surface epitopes on, either side of the receptor. Both isoforms engage in homo-dimerization, coupling variable domain D2 with D2, and D3 with D3. These interactions, involve symmetric, antiparallel pairing of identical peptide segments from, epitope I that are unique to each isoform. Structure-guided mutagenesis, and swapping of peptide segments confirm that epitope I, but not epitope, II, confers homophilic binding specificity of full-length Dscam receptors., Phylogenetic analysis shows strong selection of matching peptide sequences, only for epitope I. We propose that peptide complementarity of variable, residues in epitope I of Dscam is essential for homophilic binding, specificity.
About this StructureAbout this Structure
2V5M is a Single protein structure of sequence from Drosophila melanogaster with GOL as ligand. Structure known Active Site: AC1. Full crystallographic information is available from OCA.
ReferenceReference
Structural basis of Dscam isoform specificity., Meijers R, Puettmann-Holgado R, Skiniotis G, Liu JH, Walz T, Wang JH, Schmucker D, Nature. 2007 Aug 26;. PMID:17721508
Page seeded by OCA on Mon Nov 5 18:51:44 2007