Paper Report for: DiPaola_1990_J.Biol.Chem_265_11017
Reference
Title: Mapping the alpha-subunit site photolabeled by the noncompetitive inhibitor [3H]quinacrine azide in the active state of the nicotinic acetylcholine receptor DiPaola M, Kao PN, Karlin A Ref: Journal of Biological Chemistry, 265:11017, 1990 : PubMed
We have characterized the time-resolved labeling of a site on the Torpedo californica electrocyte acetylcholine receptor (ACHR) by the photoreactive noncompetitive inhibitor derivative quinacrine azide (QA). The dependence of [3H]QA labeling on acetylcholine (ACH) concentration and on time is consistent with the preferential labeling by [3H]QA of ACHR in the open state. The ACH-dependent [3H]QA labeling, which was associated predominantly with the alpha-subunit, was blocked by other noncompetitive inhibitors including quinacrine, chlorpromazine, proadifen, histrionicotoxin, and bupivacaine. alpha-Subunit from ACHR labeled with [3H]QA 20 ms after the addition of ACH was cleaved with CNBr, and the fragments were separated by high pressure liquid chromatography. A peptide containing a major site of specific labeling was purified on two different reverse-phase columns. By N-terminal sequencing, amino acid composition, binding to mercurial-agarose, and apparent molecular weight, this [3H]QA-labeled peptide was identified as alpha-208-243, a CNBr fragment containing the putative membrane-spanning helix M1.
        
Related information
Citations formats
DiPaola M, Kao PN, Karlin A (1990) Mapping the alpha-subunit site photolabeled by the noncompetitive inhibitor [3H]quinacrine azide in the active state of the nicotinic acetylcholine receptor Journal of Biological Chemistry265: 11017-29
DiPaola M, Kao PN, Karlin A (1990) Journal of Biological Chemistry265: 11017-29