Publication Abstract from PubMed
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.
Crystal structures of beta-neurexin 1 and beta-neurexin 2 ectodomains and dynamics of splice insertion sequence 4.,Koehnke J, Jin X, Trbovic N, Katsamba PS, Brasch J, Ahlsen G, Scheiffele P, Honig B, Palmer AG 3rd, Shapiro L Structure. 2008 Mar;16(3):410-21. PMID:18334216[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
