Channels formed by M2 peptides of a putative glutamate receptor subunit of locust
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A cDNA encoding part of a polypeptide (Loc1) that exhibits similarity to the corresponding portion of the rat GluRl subunit has been identified by screening an amplified locust cDNA library. This polypeptide is deduced to be missing about 200 amino acids of the amino-terminus and about 100 amino acids of the carboxy-terminus. cDNAs encoding two other glutamate receptor-like polypeptides (Loc2 and Loc3), which both exhibit good sequence homology with Loci, have also been identified. So far, there is no evidence for ‘flip’ and ‘flop’ variants of Loci, 2 and 3. A 27-mer peptide including the Ml sequence of Loci and a 25-mer peptide including the M2 sequence of this putative glutamate receptor subunit have been synthesised and incorporated into artificial bilayers. Channel openings, of minimum conductance 20 pS, were seen more frequently with the M2 peptide. These studies are designed to lead to the isolation of full-length cDNAs for Loci, 2 and 3 and to the electrophysiological characterisation of their ion transport properties.
KeywordsLipid Bilayer Glutamate Receptor Ibotenic Acid GluR Subunit Patch Clamp Amplifier
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