Autor: |
Matulef K; Molecular and Cellular Biology Program, University of Washington, Seattle 98105, USA., Flynn GE, Zagotta WN |
Jazyk: |
angličtina |
Zdroj: |
Neuron [Neuron] 1999 Oct; Vol. 24 (2), pp. 443-52. |
DOI: |
10.1016/s0896-6273(00)80857-0 |
Abstrakt: |
Cyclic nucleotide-gated (CNG) channels are activated in response to the direct binding of cyclic nucleotides to an intracellular domain. This domain is thought to contain a beta roll and two alpha helices, designated the B and C helices. To probe the conformational changes occurring in the ligand-binding domain during channel activation, we used the substituted cysteine accessibility method (SCAM). We found that a residue in the beta roll, C505, is more accessible in unliganded channels than in liganded channels, whereas a residue in the C helix, G597C, is more accessible in closed channels than in open channels. These results support a molecular mechanism for channel activation in which the ligand initially binds to the beta roll, followed by an opening allosteric transition involving the relative movement of the C helix toward the beta roll. |
Databáze: |
MEDLINE |
Externí odkaz: |
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