Molecular mechanism for ligand discrimination of cyclic nucleotide-gated channels
نویسندگان
چکیده
منابع مشابه
Molecular mechanism for ligand discrimination of cyclic nucleotide-gated channels
Cyclic nucleotide-gated ion channels of retinal photoreceptors and olfactory neurons are differentially activated by ligands that vary only in their purine ring structure. The nucleotide selectivity of the bovine rod cyclic nucleotide-gated channel (cGMP > cIMP >> cAMP) was significantly altered by neutralization of a single aspartic acid residue in the binding domain (cGMP > or = cAMP > cIMP)....
متن کاملCyclic Nucleotide–Gated Channels
In voltage- and cyclic nucleotide-gated ion channels, the amino-acid loop that connects the S5 and S6 transmembrane domains, is a major component of the channel pore. It determines ion selectivity and participates in gating. In the alpha subunit of cyclic nucleotide-gated channels from bovine rod, the pore loop is formed by the residues R345-S371, here called R1-S27. These 24 residues were muta...
متن کاملCyclic Nucleotide–gated Channels
abs t rac t Middendorf et al. (Middendorf, T.R., R.W. Aldrich, and D.A. Baylor. 2000. J. Gen. Physiol. 116:227– 252) showed that ultraviolet light decreases the current through cloned cyclic nucleotide–gated channels from bovine retina activated by high concentrations of cGMP. Here we probe the mechanism of the current reduction. The channels’ open probability before irradiation, P o (0), deter...
متن کاملMechanism of Tetracaine Block of Cyclic Nucleotide-gated Channels
Local anesthetics are a diverse group of ion channel blockers that can be used to probe conformational changes in the pore. We examined the effects of the local anesthetic tetracaine on rod and olfactory cyclic nucleotide-gated channels expressed from subunit 1 in Xenopus oocytes. We found that 40 microM tetracaine effectively blocked the bovine rod channel but not the rat olfactory channel at ...
متن کاملMechanism of Allosteric Modulation of Rod Cyclic Nucleotide–gated Channels
The cyclic nucleotide-gated (CNG) channel of retinal rod photoreceptor cells is an allosteric protein whose activation is coupled to a conformational change in the ligand-binding site. The bovine rod CNG channel can be activated by a number of different agonists, including cGMP, cIMP, and cAMP. These agonists span three orders of magnitude in their equilibrium constants for the allosteric trans...
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ژورنال
عنوان ژورنال: Neuron
سال: 1995
ISSN: 0896-6273
DOI: 10.1016/0896-6273(95)90150-7