Conantokin-Br from Conus brettinghami and selectivity determinants for the NR2D subunit of the NMDA receptor.
Conantokins are venom peptides from marine cone snails that are NMDA receptor antagonists. Here, we report the characterization of a 24 AA conantokin from Conus brettinghami Coomans , H. E. , Moolenbeek , R. G. and Wils , E. ( 1982 ) Basteria 46 ( 1/4 ), 3 - 67 , conantokin-Br (con-Br), the first conantokin that does not have the conserved glutamate residue at position 2. Molecular modeling studies suggest that con-Br has a helical structure between residues 2-13. In contrast to other characterized conantokins, con-Br has a high potency for NMDA receptors with NR2D subunits. To identify determinants for NR2D potency, we synthesized chimeras of con-Br and conantokin-R (con-R); the latter has a approximately 30-fold lower potency for the NR2D subtype. The characterization of two reciprocal chimeras (con-Br/R and con-R/Br), comprising the first 9-10 N-terminal AAs of each conantokin followed by the corresponding C-terminal AAs of the other conantokin demonstrates that determinants for NR2D selectivity are at the N-terminal region. Additional analogues comprising 1-3 amino acid substitutions from each peptide into the homologous region of the other led to the identification of a key determinant; a Tyr residue in position 5 increases potency for NR2D, while Val at this locus causes a decrease. The systematic definition of key determinants in the conantokin peptides for NMDA receptor subtype selectivity is an essential component in the development of conantokin peptides that are highly selective for each specific NMDA receptor subtype.
Twede
Vernon D
VD
Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA. vernon.twede@utah.edu
Teichert
Russell W
RW
Walker
Craig S
CS
Gruszczyński
Paweł
P
Kaźmierkiewicz
Rajmund
R
Bulaj
Grzegorz
G
Olivera
Baldomero M
BM
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D003198:Computer Simulation; D020916:Conotoxins / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D052078:Conus Snail / Q000737:chemistry*; D004594:Electrophysiology; D005260:Female; D020128:Inhibitory Concentration 50; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D010084:Oxidation-Reduction; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D010477:Perfusion; D017510:Protein Folding; D017433:Protein Structure, Secondary; D021122:Protein Subunits / Q000378:metabolism / Q000494:pharmacology; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D014443:Tyrosine / Q000378:metabolism; D014981:Xenopus
D020916:Conotoxins; D010455:Peptides; D021122:Protein Subunits; D016194:Receptors, N-Methyl-D-Aspartate; C541097:conantokin-Br, Conus brettinghami; D014443:Tyrosine