dc.contributor.author | Schroeder, Christina I | |
dc.contributor.author | Ekberg, Jenny | |
dc.contributor.author | Nielsen, Katherine J | |
dc.contributor.author | Adams, Denise | |
dc.contributor.author | Loughnan, Marion L | |
dc.contributor.author | Thomas, Linda | |
dc.contributor.author | Adams, David J | |
dc.contributor.author | Alewood, Paul F | |
dc.contributor.author | Lewis, Richard J | |
dc.date.accessioned | 2017-05-03T16:58:38Z | |
dc.date.available | 2017-05-03T16:58:38Z | |
dc.date.issued | 2008 | |
dc.date.modified | 2009-11-25T07:59:58Z | |
dc.identifier.issn | 0021-9258 | |
dc.identifier.doi | 10.1074/jbc.M802852200 | |
dc.identifier.uri | http://hdl.handle.net/10072/26889 | |
dc.description.abstract | μ-Conotoxins are small peptide inhibitors of muscle and neuronal tetrodotoxin (TTX)-sensitive voltage-gated sodium channels (VGSCs). Here we report the isolation of μ-conotoxins SIIIA and SIIIB by 125I-TIIIA-guided fractionation of milked Conus striatus venom. SIIIA and SIIIB potently displaced 125I-TIIIA from native rat brain Nav1.2 (IC50 values 10 and 5 nM, respectively) and muscle Nav1.4 (IC50 values 60 and 3 nM, respectively) VGSCs, and both inhibited current through Xenopus oocyte-expressed Nav1.2 and Nav1.4. An alanine scan of SIIIA-(2–20), a pyroglutamate-truncated analogue with enhanced neuronal activity, revealed residues important for affinity and selectivity. Alanine replacement of the solvent-exposed Trp-12, Arg-14, His-16, Arg-18 resulted in large reductions in SIIIA-(2–20) affinity, with His-16 replacement affecting structure. In contrast, [D15A]SIIIA-(2–20) had significantly enhanced neuronal affinity (IC50 0.65 nM), while the double mutant [D15A/H16R]SIIIA-(2–20) showed greatest Nav1.2 versus 1.4 selectivity (136-fold). 1H NMR studies revealed that SIIIA adopted a single conformation in solution comprising a series of turns and anα-helical motif across residues 11–16 that is not found in larger μ-conotoxins. The structure of SIIIA provides a new structural template for the development of neuronally selective inhibitors of TTX-sensitive VGSCs based on the smaller μ-conotoxin pharmacophore. | |
dc.description.peerreviewed | Yes | |
dc.description.publicationstatus | Yes | |
dc.language | English | |
dc.language.iso | eng | |
dc.publisher | The American Society for Biochemistry and Molecular Biology | |
dc.publisher.place | United States of America | |
dc.publisher.uri | http://www.jbc.org/ | |
dc.relation.ispartofstudentpublication | N | |
dc.relation.ispartofpagefrom | 21621 | |
dc.relation.ispartofpageto | 2128 | |
dc.relation.ispartofissue | 31 | |
dc.relation.ispartofjournal | The Journal of Biological Chemistry | |
dc.relation.ispartofvolume | 283 | |
dc.rights.retention | Y | |
dc.subject.fieldofresearch | Chemical sciences | |
dc.subject.fieldofresearch | Biological sciences | |
dc.subject.fieldofresearch | Cell neurochemistry | |
dc.subject.fieldofresearch | Biomedical and clinical sciences | |
dc.subject.fieldofresearchcode | 34 | |
dc.subject.fieldofresearchcode | 31 | |
dc.subject.fieldofresearchcode | 310104 | |
dc.subject.fieldofresearchcode | 32 | |
dc.title | Neuronally Selective μ-conotoxins From Conus Stiatus Utilize an α-Helical Motif to Mammalian Sodium Channels | |
dc.type | Journal article | |
dc.type.description | C1 - Articles | |
dc.type.code | C - Journal Articles | |
gro.date.issued | 2008 | |
gro.hasfulltext | No Full Text | |
gro.griffith.author | Ekberg, Jenny A. | |