Chimeric analysis of a neuronal nicotinic acetylcholine receptor reveals amino acids conferring sensitivity to α-bungarotoxin

49Citations
Citations of this article
13Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

We have investigated the molecular determinants responsible for α- bungarotoxin (αBgtx) binding to nicotinic acetylcholine receptors through chimeric analysis of two homologous α subunits, one highly sensitive to αBgtx block (α1) and the other, αBgtx-insensitive (α3). By replacing rat α3 residues 184-191 with the corresponding region from the Torpedo α1 subunit, we introduced a cluster of five α1 residues (Trp-184, Trp-187, Val- 188, Tyr-189, and Thr-191) into the α3 subunit. Functional activity and αBgtx sensitivity were assessed following co-expression in Xenopus oocytes of the chimeric α3 subunit (α3/α1[5]) with either rat β2 or β4 subunits. Agonist-evoked responses of α3/α1[5]-containing receptors were blocked by αBgtx with nanomolar affinity (IC50 values: 41 nM for α3/α[5]β2 and 19 nM for α3/α1[5]β4). Furthermore, receptors containing the single point mutation α3K189Y acquire significant sensitivity to αBgtx block (IC50 values: 186 nM for α3K189Yβ2 and 179 nM for α3K189Yβ4). Another α3 chimeric subunit, α3/α7[6], similar to α3/α1[5] but incorporating the corresponding residues from the αBgtx-sensitive α7 subunit, also conferred potent αBgtx sensitivity to chimeric receptors when co-expressed with the β4 subunit (IC50 value = 31 nM). Our findings demonstrate that the residues between positions 184 and 191 of the αBgtx-sensitive subunits α1 and α7 play a critical functional role in the interaction of αBgtx with nicotinic acetylcholine receptors sensitive to this toxin.

Cite

CITATION STYLE

APA

Levandoski, M. M., Lin, Y., Moise, L., McLaughlin, J. T., Cooper, E., & Hawrot, E. (1999). Chimeric analysis of a neuronal nicotinic acetylcholine receptor reveals amino acids conferring sensitivity to α-bungarotoxin. Journal of Biological Chemistry, 274(37), 26113–26119. https://doi.org/10.1074/jbc.274.37.26113

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free