Sodium channel from rat brain: role of the. beta. 1 and. beta. 2 subunits in saxitoxin binding
Procedures are described for the selective removal of the ..beta..1 or the ..beta..2 subunits from the detergent-solubilized channel from rat brain, and the functional integrity of the resulting protein complex is examined. Treatment of the channel with 1.0 M MgCl/sub 2/ followed by sedimentation through sucrose gradients results in complete separation of ..beta..1 from the ..cap alpha..-..beta..2 complex and complete loss of (/sup 3/H)saxitoxin (STX) binding activity. At intermediate MgCl/sub 2/ concentrations, the loss of ..beta..1 and the loss of (/sup 3/H)STX binding activity are closely correlated. Tetrodotoxin (TTX) quantitatively stabilizes the solubilized complex against both the loss of ..beta..1 and the loss of (/sup 3/H)STX binding activity. This indicates that association of the ..cap alpha.. and ..beta..1 subunits is required to maintain the STX/TTX binding site in a conformation with high affinity for STX and TTX in the detergent-solubilized state. Treatment of the solubilized sodium channel with dithiothreitol in the presence of TTX causes specific release of the ..beta..2 subunit, without significantly removing ..beta..1. There is little or no correlation between the amount of ..beta..2 in the sodium channel complex and the ability of the preparation to bind (/sup 3/H)STX.
- Research Organization:
- Univ. of Washington, Seattle
- OSTI ID:
- 5179130
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 261:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BRAIN
PROTEINS
BIOCHEMICAL REACTION KINETICS
SEPARATION PROCESSES
EXPERIMENTAL DATA
PURIFICATION
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMALS
BODY
CENTRAL NERVOUS SYSTEM
DATA
INFORMATION
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
NERVOUS SYSTEM
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANS
REACTION KINETICS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques