Protein structural effects of agonist binding to the nicotinic acetylcholine receptor

FEBS Letters

Castresana, Jose²  Laynez, Jose L.¹  Fernandez-Ballester, Gregorio³  Arrondo, Jose-Luis R.²  Ferragut, Jose A.³  Fernandez, Asia M.³  Gonzalez-Ros, Jose M.³ 

[1] Instituto de Quimica-Fisica Rocasolano, C.S.I.C., Serrano 119, 28006 Madrid, Spain;Department of Biochemistry, Faculty of Sciences, University of the Basque Country, 48080 Bilbao, Spain;Department of Neurochemistry and Institute of Neurosciences, University of Alicante, 03080 Alicante, Spain

关键词: Torpedo acetylcholine receptor;    Fourier-transform infrared spectroscopy;    Quantitative estimation of secondary structure;    Differential scanning calorimetry;    Thermal stability;    AcChR;    acetylcholine receptor;    α-Bgt;    α-bungarotoxin;    FT-IR;    Fourier-transform infrared spectroscopy;    DSC;    differential scanning calorimetry;   

DOI  :  10.1016/0014-5793(92)80967-L

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The effects on the protein structure produced by binding of cholinergic agonists to purified acetylcholine receptor (AcChR) reconstituted into lipid vesicles, has been studied by Fourier-transform infrared spectroscopy and differential scanning calorimetry. Spectral changes in the conformationally sensitive amide 1 infrared band indicates that the exposure of the AcChR to the agonist carbamylcholine, under conditions which drive the AcChR into the desensitized state, produces alterations in the protein secondary structure. Quantitative estimation of these agonist-induced alterations by band-fitting analysis of the amide 1 spectral band reveals no appreciable changes in the percent of α-helix, but a decrease in β-sheet structure, concomitant with an increase in less ordered structures. Additionally, agonist binding results in a concentration-dependent increase in the protein thermal stability, as indicated by the temperature dependence of the protein infrared spectrum and by calorimetric analysis, which further suggest that AcChR desensitization induced by the cholinerpic agonist implies significant rearrangements in the protein structure.

【 授权许可】

Unknown