Download MendeleyCrystal Structures of beta-Neurexin 1 and beta-Neurexin 2 Ectodomains and Dynamics of Splice Insertion Sequence 4.
Koehnke, J., Jin, X., Trbovic, N., Katsamba, P.S., Brasch, J., Ahlsen, G., Scheiffele, P., Honig, B., Palmer, A.G., Shapiro, L.(2008) Structure 16: 410-421
- PubMed: 18334216
- DOI: https://doi.org/10.1016/j.str.2007.12.024
- Primary Citation of Related Structures:
3BOD, 3BOP - PubMed Abstract:
Presynaptic neurexins (NRXs) bind to postsynaptic neuroligins (NLs) to form Ca(2+)-dependent complexes that bridge neural synapses. beta-NRXs bind NLs through their LNS domains, which contain a single site of alternative splicing (splice site 4) giving rise to two isoforms: +4 and Delta. We present crystal structures of the Delta isoforms of the LNS domains from beta-NRX1 and beta-NRX2, crystallized in the presence of Ca(2+) ions. The Ca(2+)-binding site is disordered in the beta-NRX2 structure, but the 1.7 A beta-NRX1 structure reveals a single Ca(2+) ion, approximately 12 A from the splice insertion site, with one coordinating ligand donated by a glutamic acid from an adjacent beta-NRX1 molecule. NMR studies of beta-NRX1+4 show that the insertion sequence is unstructured, and remains at least partially disordered in complex with NL. These results raise the possibility that beta-NRX insertion sequence 4 may function in roles independent of neuroligin binding.
Organizational Affiliation:
Department of Biochemistry and Molecular Biophysics, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
