Solution NMR of acetylcholine binding protein reveals agonist-mediated conformational change of the C-loop.

Solution NMR of acetylcholine binding protein reveals agonist-mediated conformational change of the C-loop. Research Abstract Details 

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Solution NMR of acetylcholine binding protein reveals agonist-mediated conformational change of the C-loop. Abstract Text:

Fan Gao,Georges Mer,Marco Tonelli,Scott B Hansen,Thomas P Burghardt,Palmer Taylor,Steven M Sine,

Previous X-ray crystallography, molecular dynamics simulation, fluorescence spectroscopy, and deuterium-hydrogen exchange of acetylcholine binding protein (AChBP) suggest that after binding of the agonist, the C-loop at the periphery of the binding site draws inward to cap the site and envelop the agonist. In this study, we use high-resolution solution NMR to monitor changes in the chemical environment of the C-loop without and with acetylcholine (ACh) bound. Substitution of [15N]cysteine for the native cysteines 123, 136, 187, and 188 provided intrinsic monitors of the chemical environments of the Cys- and C-loops, respectively. Two-dimensional transverse relaxation-optimized spectroscopy 15N-1H HSQC spectroscopy of apo-AChBP revealed seven well resolved cross-peaks for the group of cysteines. The spectrum of AChBP with Ser substituted for Cys 187 and 188 shows only two main cross-peaks, corresponding to Cys 123 and 136 from the Cys-loop, enabling resonance assignments. After binding of ACh, the five cross-peaks associated with cysteines from the C-loop condense into two predominant cross-peaks not observed in the spectrum from the apo protein, indicating a restricted range of conformations and change in chemical environment of the C-loop. The results show that isotopic cysteine can be incorporated into specified positions of AChBP expressed from a eukaryotic source, that the C-loop assumes multiple conformations without ACh, but that its conformation becomes restricted with ACh bound. The collective findings suggest a structural mechanism for agonist recognition in AChBP and related Cys-loop receptors.

Solution NMR of acetylcholine binding protein reveals agonist-mediated conformational change of the C-loop. Publishing Authors By Initials

F Gao,G Mer,M Tonelli,SB Hansen,TP Burghardt,P Taylor,SM Sine,

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Solution NMR of acetylcholine binding protein reveals agonist-mediated conformational change of the C-loop. Journal Published:

PUBLICATION TYPE: Research Support, N.I.H., Extr

Journal: Molecular pharmacology

VOLUME: 70

Page Numbers: 1230-5

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ISSN: 0026-895X

DAY: 17

MONTH: 07

YEAR: 2006

Solution NMR of acetylcholine binding protein reveals agonist-mediated conformational change of the C-loop. Information

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LANGUAGE: eng

NlmUniqueID: 35623

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Grant and Affiliation Information for Solution NMR of acetylcholine binding protein reveals agonist-mediated conformational change of the C-loop.

AFFILIATION: Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester MN 55905, USA.

Country: United States

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MEDLINETA: Mol Pharmacol

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