Molecular weight and structural nonequivalence of the mature ɑ subunits of Torpedo californica acetylcholine receptor
Abstract
A discrepancy of about 20% exists between the molecular weight of the ɑ subunit of Torpedo californica electroplax acetylcholine receptor as determined by gel electrophoresis of the mature protein (M_r 40,000 ± 2000) and by nucleotide sequence analysis of cDNA (M_r ≈z50,000). We demonstrate by amino acid sequence analysis that post-translational processing does not occur and that the mature subunit has a M_r of ≈50,000. The functional acetylcholine receptor contains two copies of this ɑ subunit in addition to one each of related β, y, and δ subunits. The binding sites for cholinergic ligands that are located on the a subunits have been shown to be nonequivalent. Amino acid sequence analysis of peptides obtained by proteolytic cleavage of the a subunit reveals that N-asparagine glycosylation at a single site (residue 141) occurs to a different extent in the two copies of this polypeptide in the mature protein and provides an explanation for nonequivalence of their binding sites.
Additional Information
© 1984 National Academy of Sciences. Communicated by John D. Roberts, December 27, 1983. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.Attached Files
Published - CONpnas84.pdf
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Additional details
- PMCID
- PMC345123
- Eprint ID
- 32219
- Resolver ID
- CaltechAUTHORS:20120702-070128826
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2012-07-02Created from EPrint's datestamp field
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2021-11-09Created from EPrint's last_modified field