Raman spectroscopic study on the conformation of 11 S form acetylcholinesterase from <i>Torpedo californica</i>

Aslanian, Dimitrina; Gróf, Pál; Négrerie, Michel; Bałkanski, M.; Taylor, Palmer

doi:10.1016/0014-5793(87)81216-4

Cited by 9 publications

(3 citation statements)

References 28 publications

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“…Also, using CD spectroscopy a content of 33% a-helix, 23% P-sheet (14% antiparallel and 9% parallel), 17% turns and 26% other structure for the tetrameric 11-S AChE has been established (Manavalan et al, 1985). Vibrational-Raman spectroscopy, of the same AChE molecular form, yielded 49 % a-helical structure, 23 % p-sheet, 11% turns and undefined structure (Aslanian et al, 1987;Aslanian et al, 1991).…”

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confidence: 97%

Secondary structure and temperature behaviour of acetylcholinesterase

Görne-Tschelnokow

Naumann

Weise

et al. 1993

European Journal of Biochemistry

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The secondary structure of the acetylcholinesterase and its temperature behaviour have been investigated using Fourier-transform infrared (FTIR) spectroscopy. The data are compared to the structure obtained by X-ray analysis of the crystalline enzyme. The secondary structure was determined using the spectral features observed in the amide-I band (H,O buffer) and amide-I' band (D,O buffer) at 1600-1700 cm-I, taking advantage of resolution-enhancement techniques along with least-squares band-fitting procedures. The relative amounts of different secondary-structure elements, 34-36% for a-helices, 19-25% for p-sheets, 15-16% for turns and 13-17% for irregular structures, were estimated. These data, obtained with the enzyme in solution, correlate well with X-ray data of the crystalline protein [Sussman, J. L., Hard, M., Frolow, F., Oefner, C., Goldman, A., Toker, L. The relationship between the thermally induced loss of enzyme activity and secondary-structure changes has also been investigated. The decrease in enzyme activity to zero at 30-40 "C was accompanied only by minor changes in the secondary structure. At 55-6OoC, denaturation of AChE occurs. In this temperature range, all bands assigned to the various secondary-structure elements abruptly disappear in a co-operative and irreversible manner, whereas the &aggregation bands (at 1622 cm-' and the corresponding high-frequency band) increase in intensity at the same rate.Acetylcholinesterase (AChE) is a key molecule involved in nerve-impulse transmission at cholinergic synapses. It rapidly hydrolyses the neurotransmitter acetylcholine and thus terminates the signal. As the main point of attack of most insecticides and chemical-warfare agents (nerve gases), AChE is of considerable interest. Moreover, structural research on AChFi is relevant because AChE is the best characterized member of the protein family of serine esterases, as defined on the basis of sequence homology (Myers et al., 1988;Krejci et al., 1991;Ollis et al., 1992). Since disulfide bridges are highly conserved within this protein family, it is plausible that AChE shares secondary-structure and tertiarystructure motifs with these related proteins.The three-dimensional structure of crystallized AChEi has been recently reported (Sussman et al., 1991). The AChE monomer is an ellipsoidally shaped alp-protein, with dimensions of 4.3 nm X 6.0 nm X 6.5 nm, which contains a 12-stranded mixed P-sheet surrounded by 14 a-helices. From the X-ray data, it can be concluded that the a-structure content is approximately 32% and that the p-structure content is 15 %. Even with detailed structural information from X-ray crystallography, spectroscopic methods for investigating secondary structure have not lost their attraction. Firstly, spectroscopic methods allow the direct measurement of proteins in solution (in a more native state) and they have considerable potential for exploring conformational changes, such as temperature-dependent processes, which might not, in principle, be amenable to X-ray analysis. Secondly, ...

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confidence: 97%

Secondary structure and temperature behaviour of acetylcholinesterase

Görne-Tschelnokow

Naumann

Weise

et al. 1993

European Journal of Biochemistry

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“…The normalized intensity was compared to a set of reference Raman spectra from proteins, the structure of which have been determined by X-ray diffraction. We have used the data set from Williams' method (1986), and we have already applied this technique to another protein in solution, the enzyme acetylcholinesterase (Aslanian et al, 1987).…”

Section: Methodsmentioning

confidence: 99%

Structure and chemical modifications of neurotoxin from Naja nigricollis studied by Raman spectroscopy

Négrerie¹,

Gróf²,

Bouet³

et al. 1990

Biochemistry

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Raman spectroscopy was used to determine structural features of the native toxin alpha from Naja nigricollis, which contains only one Trp and one Tyr, and of chemically modified toxins having chromophores added to these two conserved aromatic amino acids. The percentages of secondary structure were determined by using amide I polypeptidic vibration analysis and are in agreement with X-ray structure [Low et al. (1976) Proc. Natl. Acad Sci. U.S.A. 73, 2991-2994] as well as with the geometry of the disulfide bridges estimated by using the v(S-S) vibrations. In the native toxin alpha, the single invariant tyrosine 25 appears to be buried in the structure and involved in a strong hydrogen bond. We have chemically modified these two invariant aromatic side chains by addition of chromophores. The presence of a (nitrophenyl)sulfenyl (NPS) chromophore bound to the Trp does not perturb the secondary structure of the toxin as shown by the analysis of the polypeptidic amide I vibrations; however, the environment of this Trp and the geometry of a disulfide bridge seem to be modified. The secondary structure is not affected by the presence of the NPS chromophore; therefore, the decrease in binding affinity observed after modification of Trp-29 by the reagent NPS-Cl [Faure et al. (1983) Biochemistry 22, 2068-2076] is due to an alteration of the environment of this aromatic amino acid and/or a steric hindrance and not to an overall modification of the toxin structure. The binding assays of [nitrotyrosyl]toxin show that after nitration the affinity toward the monoclonal antibody M alpha 1 is unchanged and that the affinity toward the cholinergic receptor (AcChR) from Torpedo marmorata remains high. We concluded that the structure of toxin alpha after adding the NO2 chromophore to Tyr-25 is the same as it is in native toxin.

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“…Detailed Raman vibrational assignments of AChE can be found in the literature. 37,38 The most prominent band that originates from the silica matrix in poly(L-lysine) templated silica nanocomposites is found near 490 cm À1 which can be attributed to Si-O-Si bending vibrations. The assignment of this mode is based on reports on sol-gel derived organically modified silicates.…”

Section: Raman Spectroscopymentioning

confidence: 99%