Identification of a phenylalkylamine binding region within the. alpha. 1 subunit of skeletal muscle Ca sup 2+ channels

Journal Article · Sat Dec 01 00:00:00 EST 1990 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.87.23.9108· OSTI ID:5999825

Striessnig, J; Catterall, W A ^[1]; Glossmann, H ^[2]

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1. Univ. of Washington, Seattle (United States)
2. Inst. of Biochemical Pharmacology, Innsbruck (Austria)

The {alpha}1 subunit of the skeletal muscle Ca{sup 2+} channel has been specifically photoaffinity labeled with the phenylalkylamine-receptor-selective verapamil derivative ({minus})-5-(3-azidophenethyl(N-methyl-{sup 3}H)methylamino)-2-(3,4,5-trimethoxyphenyl)-2-isopropylvaleronitrile ((N-methyl-{sup 3}H)LU49888). Proteolytic fragments generated by various endoproteases were probed by immunoprecipitation with several sequence-specific antibodies to determine the site of labeling within the primary structure of {alpha}1. These results restrict the site of photolabeling by (N-methyl-{sup 3}H)LU49888 to the region between Glu-1349 and Trp-1391. This segment of {alpha}1 contains transmembrane helix S6 of domain IV and the beginning of the long intracellular C-terminal tail. Because the phenylalkyl-amine receptor site is only accessible from the intracellular side of the Ca{sup 2+} channel, we propose that the intracellular end of helix IVS6 and the adjacent intracellular amino acid residues play an essential role in formation of the phnylalkylamine receptor site. The action of the phenylalkylamines as open channel blockers suggests that this region may also contribute to formation of the intracellular opening of the transmembrane pore of the Ca{sup 2+} channel.

• OSTI ID: 5999825
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 87:23; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CALCIUM COMPOUNDS
MEMBRANE TRANSPORT
MEMBRANE PROTEINS
AUTORADIOGRAPHY
RECEPTORS
METHYLATION
ALKYLATION
AMINES
CELL MEMBRANES
MUSCLES
PRECIPITATION
TRITIUM COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
HYDROGEN COMPOUNDS
MEMBRANES
ORGANIC COMPOUNDS
PROTEINS
SEPARATION PROCESSES
550201* - Biochemistry- Tracer Techniques