Structure of the First Transmembrane Domain of the Neuronal Acetylcholine Receptor β2 Subunit

Bondarenko, Vasyl; Xu, Yan; Tang, Pei

doi:10.1529/biophysj.106.095364

Cited by 9 publications

(8 citation statements)

References 57 publications

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“…The disruption of helical structure at this site was also observed in our previous NMR experiments on the isolated TM1 helix in DPC detergent, where the helical structure extended from L35 to F50 [54]. Thus, the helical kink at L35 seems to be an intrinsic property of the protein and independent of the membrane mimetic.…”

Section: Resultssupporting

confidence: 70%

NMR structure of the transmembrane domain of the n-acetylcholine receptor β2 subunit

Bondarenko

Tillman

et al. 2010

Biochimica et Biophysica Acta (BBA) - Biomembranes

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SUMMARY Nicotinic acetylcholine receptors (nAChRs) are involved in fast synaptic transmission in the central and peripheral nervous system. Among the many different types of subunits in nAChRs, the β2 subunit often combines with the α4 subunit to form α4β2 pentameric channels, the most abundant subtype of nAChRs in the brain. Besides computational predictions, there is limited experimental data available on the structure of the β2 subunit. Using high-resolution NMR spectroscopy, we solved the structure of the entire transmembrane domain (TM1234) of the β2 subunit. We found that TM1234 formed a four-helix bundle in the absence of the extracellular and intracellular domains. The structure exhibited many similarities to those previously determined for the Torpedo nAChR and the bacterial ion channel GLIC. We also assessed the influence of the fourth transmembrane helix (TM4) on the rest of the domain. Although secondary structures and tertiary arrangements were similar, the addition of TM4 caused dramatic changes in TM3 dynamics and subtle changes in TM1 and TM2. Taken together, this study suggests that the structures of the transmembrane domains of these proteins are largely shaped by determinants inherent in their sequence, but their dynamics may be sensitive to modulation by tertiary and quaternary contacts.

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Section: Resultssupporting

confidence: 70%

NMR structure of the transmembrane domain of the n-acetylcholine receptor β2 subunit

Bondarenko

Tillman

et al. 2010

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…1998a). Studies in the nAChR α2 subunit using nuclear magnetic resonance predicted that the TM1 alpha helix begins two residues before the proline and that the proline promotes non‐helical structure in this region (Bondarenko et al. 2007).…”

Section: Discussionmentioning

confidence: 99%

Cross‐linking of sites involved with alcohol action between transmembrane segments 1 and 3 of the glycine receptor following activation

Lobo

Harris

Trudell

2007

Journal of Neurochemistry

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J. Neurochem. (2008) 104, 1649–1662. Abstract The glycine receptor is a member of the Cys‐loop, ligand‐gated ion channel family and is responsible for inhibition in the CNS. We examined the orientation of amino acids I229 in transmembrane 1 (TM1) and A288 in TM3, which are both critical for alcohol and volatile anesthetic action. We mutated these two amino acids to cysteines either singly or in double mutants and expressed the receptors in Xenopus laevis oocytes. We tested whether disulfide bonds could form between A288C in TM3 paired with M227C, Y228C, I229C, or S231C in TM1. Application of cross‐linking (mercuric chloride) or oxidizing (iodine) agents had no significant effect on the glycine response of wild‐type receptors or the single mutants. In contrast, the glycine response of the I229C/A288C double mutant was diminished after application of either mercuric chloride or iodine only in the presence of glycine, indicating that channel gating causes I229C and A288C to fluctuate to be within 6 Å apart and form a disulfide bond. Molecular modeling was used to thread the glycine receptor sequence onto a nicotinic acetylcholine receptor template, further demonstrating that I229 and A288 are near‐neighbors that can cross‐link and providing evidence that these residues contribute to a single binding cavity.

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“…NMR can be used not only to determine anesthetic interaction sites,15-17 but also to divulge anesthetic-triggered changes in protein structures and dynamics 15,16,18,19. These have been successfully demonstrated for isolated domains of the α4β2 nAChR 17,20,21. Photo-affinity labeling revealed specific binding sites in the Torpedo nAChR for several different anesthetics,22-26 but there is no report in the literature about anesthetic photolabling to the α4β2 nAChR.…”

Section: Introductionmentioning

confidence: 99%

General Anesthetic Binding to Neuronal α4β2 Nicotinic Acetylcholine Receptor and Its Effects on Global Dynamics

Liu

Willenbring

et al. 2009

J. Phys. Chem. B

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The neuronal α4β2 nicotinic acetylcholine receptor (nAChR) is a target for general anesthetics. Currently available experimental structural information is inadequate to understand where anesthetics bind and how they modulate the receptor motions essential to function. Using our published open-channel structure model of α4β2 nAChR, we identified and evaluated six amphiphilic interaction sites for the volatile anesthetic halothane via flexible ligand docking and subsequent 20-ns molecular dynamics simulations. Halothane binding energies ranged from −6.8 to −2.4 kcal/mol. The primary binding sites were located at the interface of extracellular and transmembrane domains, where halothane perturbed conformations of, and widened the gap among, the Cys-loop, the β1-β2 loop, and the TM2-TM3 linker. The halothane with the highest binding affinity at the interface between the α4 and β2 subunits altered interactions between the protein and nearby lipids by competing for hydrogen bonds. Gaussian network model analyses of the α4β2 nAChR structures at the end of 20-ns simulations in the absence or presence of halothanes revealed profound changes in protein residue mobility. The concerted motions critical to protein function were also perturbed considerably. Halothane's effect on protein dynamics was not confined to the residues adjacent to the binding sites, indicating an action on a more global scale.

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Structure of the First Transmembrane Domain of the Neuronal Acetylcholine Receptor β2 Subunit

Cited by 9 publications

References 57 publications

NMR structure of the transmembrane domain of the n-acetylcholine receptor β2 subunit

NMR structure of the transmembrane domain of the n-acetylcholine receptor β2 subunit

Cross‐linking of sites involved with alcohol action between transmembrane segments 1 and 3 of the glycine receptor following activation

General Anesthetic Binding to Neuronal α4β2 Nicotinic Acetylcholine Receptor and Its Effects on Global Dynamics

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