Dimitrina Aslanian

Raman spectroscopy of acetylcholine receptor-rich membranes from Torpedo marmorata and of their isolated components

not received Acetylcholine receptor Lipid-protein interaction Raman spectroscopy is a particularly powerful technique to explore the three-dimensional organisation of biological molecules. With proteins, this method lead to the detection of differences in conformation affecting both the backbone and the amino acid side chains [l]. In particular, the analysis of the conformationally sensitive Amide I and Amide III regions of the spectra offered new insights and predictions on the secondary folding of the polypeptide chain. Also, the vibrations of the amino acid side chains, in particular those of the aromatic amino acids tyrosine and tryptophan, brought original information on the state of these residues in proteins [2,3]. With simple lipids and model membrane systems the Raman active (C-H) and (C-C) stretching modes have been used to monitor lateral mobility and trans-gauche isomerism [4,5]. Various lipid-protein complexes have also been the object of intense Raman studies [6-81 and the analysis extended to biological membranes from human and rabbit erythrocyte ghosts [9, lo], thymocytes [ 111, sarcoplasmic reticulum [ 121, hamster lymphocytes [13] and human blood platelets [14]. Abbreviations: AcCh, acetylcholine; AcChR, acetylcholine receptor; DDAO, dimethyldodecylamine oxide Published by Elsevier Science Publishers B. V. Within the framework of the vibrational spectroscopic studies on the conformation of acetylcholine (AcCh) and related compounds (rv 50 mM Tris-HCl (pH 7.5), 3 mM EDTA, 1 mM EGTA, 0.1 mM PMSF, 5 units/ml aprotinin, 5 pg/ml pepstatin; see [ 181). The mem00145793/83/

Vibrational spectroscopic approach to the study of acetylcholine and related compounds

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Raman spectroscopic study on the conformation of 11 S form acetylcholinesterase from Torpedo californica

The present review reports the coordinated application of three spectroscopic methods (Raman, infrared(IR) and inelastic electron tunneling spectroscopy (IETS)) in the study of the conformation of Ach and some analogues (beta-MeAch, Mu and Nic) in solid state, aqueous solution and in interaction with a surface. Useful correlated information is obtained by Raman and IR spectroscopies on the conformational possibilities of these molecules in transition from solid state to aqueous solution. With this information in hand as well as on the basis of Raman and IR study of the nonenzymatic hydrolysis of Ach, the first detailed experimental investigation of the interaction of Ach and beta-MeAch adsorbed on a surface (A1203) is realised by the IETS method. The results are used to discuss an interaction analogous to that of Ach with receptor and another one analogous to that of Ach and AchE.

Changes of phage T7 nucleoprotein structure at low ionic strength. A Raman spectroscopic study

Vibrational Raman spectroscopy has been used to study the conformation of the 11 S form of acetylcholine‐sterase from Torpedo californica. Secondary structure analysis by the method of Williams [(1983) J. Mol. Biol. 166, 581–603] shows 49% α‐helical structure, 23% β‐sheets, 11% turns and 15% undefined structure. Secondary structure estimates obtained for this enzyme by Raman spectroscopy and circular dichroism have been analyzed.

Raman and Infrared Study of Acetylcholine and Postsynaptic Membranes

To detect changes in DNA and/or protein structures of phage T7 under different ionic strength, Raman spectra of phage T7 have been recorded in solutions of three different NaCl + Tris concentrations. Iterative Jansson-Van Cittert deconvolution, as well as decomposition methods have been used to quantify changes in DNA structure. Significant modifications in ratios of contributions from 675 and 685 per cm vibrations, as well as in the DNA backbone vibrations, characteristic for B-DNA, near 835 per cm frequency have been found. Changes of the base electronic structure were identified in the interval between 1280 and 1400 cm(-1). Estimation of the overall protein structure suggests predominant beta-sheet content.

A Raman spectroscopic study of acctylcholine receptor-rich membranes from Torpedo marmorata. Interaction of the receptor with carbamylcholine and ( + )-tubocurarine

Raman and infrared (IR) spectroscopies provide largely complementary information on the structure and interaction of organic and biological molecules [1–6].