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- Antzutkin, Oleg, et al.
(author)
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Binding of Aluminium(III)-Citrate Complexes, [Al3(H-1Cit)3(OH)]-4 and [Al3(H-1Cit)3(OH)4]-7, to Alzheimer's A-beta(1-40) Peptides : In situ Atomic Force, Electron Microscopy and Solid State 13C and 27Al NMR Studies
- 2005
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In: Sixth Keele Meeting on Aluminium. - : Centro de Estudos do Ambiente e Mar, Universidade de Aveiro. ; , s. 16-
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Conference paper (other academic/artistic)abstract
- It is believed that Alzheimer's disease (AD) amyloid-β-peptide (Aβ) deposits contribute directly to the disease's progressive neurodegeneration. Aggregation cascade for Aβ peptides, its relevance to neurotoxicity in the course of AD, various factors modulating Aβ aggregation kinetics and experimental methods useful for these studies were recently discussed [1]. Al(III), Zn(II), Cu(II) and Fe(III) ions are often colocalized at the center of the core of Alzheimer's amyloid plaques [2] and are suggested to promote aggregation of physiological concentrations of Aβ [3]. It has also been suggested that Al can block calcium permeable putative Aβ-peptide channels in bilayer membranes [4]. Therefore studies of complexation of metal ions with Aβ-oligomers and fibrils are important in the search for the causes of and potential treatments for AD.We studied effects of highly soluble and biologically relevant aluminium(III)-citrate compounds, [Al3(H-1Cit)3(OH)]-4 and [Al3(H-1Cit)3(OH)4]-7, on the fibrillogenesis of Aβ(1-40). All resonances in 156.37 MHz 27Al and 90.52 MHz 13C MAS NMR spectra of powder Al(III)-citrate complexes were assigned. 27Al MAS NMR of dialysed samples of Aβ(1-40) co-incubated with the Al(III)-citrate complexes at different concentrations in TRIS buffer solutions, pH 7.4, shows that Al(III)-citrates bind to Aβ(1-40) as [Al3(H-1Cit)3(OH)]-4 and either accelerate ([Al3(H-1Cit)3(OH)]-4 complex) or retard ([Al3(H-1Cit)3(OH)4]-7 compound) aggregation of Aβ(1-40) as revealed by AFM. [1] ON Antzutkin, Magn. Reson. Chem. 42 (2004) 231; [2] MA Lovell et al., J. Neurol. Sci. 158 (1998) 47; Ch Exley et al., Al and Alzheimer's disease, Ch Exley (Ed)1998) 47; Ch Exley , Ch Exley (Ed) Elsevier Science, 2001, 421; [3] PW Mantyh et al., J. Neurochem. 61 (1993) 1171; [4] N Arispe et al, PNAS 90 (1993) 567.
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- Antzutkin, Oleg, et al.
(author)
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Exploring solid-state 17O NMR to distinguish secondary structures in Alzheimer's Aβ fibrils
- 2009
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In: Euromar 2009. ; , s. 107-
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Conference paper (other academic/artistic)abstract
- It has been shown by a large number of studies that Alzheimer's disease (AD) amyloid-β-peptide (Aβ) deposits contribute directly to the disease's progressive neurodegeneration. Aggregation cascade for Aβ peptides, its relevance to neurotoxicity in the course of AD, various factors modulating Aβ aggregation kinetics and experimental methods useful for these studies were recently discussed [1]. Results of Tycko and co-workers point at neurotoxicity in vitro of the two different types of Alzheimer's amyloid fibrils dispersed by ultrasonication into small fragments [2]. The high toxicity of Aβ oligomers in vitro has been discussed by Stege et. al who have found that the molecular chaperone αB-crystallin prevents Aβ from forming amyloid fibrils but nevertheless enhances Aβ toxicity [3]. Glabe and co-workes successfully prepared antibodies for Aβ oligomers and small spherical aggregates using nanogold technology [4]. They also have shown that these antibodies decrease toxicity of Aβ for SH-SY5Y human neuroblastoma cell cultures in vitro [4]. In this concern both structure of Aβ-oligomers/fibrils and the specific interaction (aggregation/fusion) of Aβ peptides with nerve cell membranes is of a particular importance [5].We explore Solid-State 17O NMR on selectively 17O,13C,15N-labeled Aβ(1-40), Aβ(11-25) and Ac-Aβ(16-22)-NH2 peptides to distinguish a parallel and anti-parallel β-sheet secondary structures in β-NH2 peptides to distinguish a parallel and anti-parallel β-sheet secondary structures in amyloid fibrils. Aβ(1-40) fibrils form in-registry parallel β-sheets [6], while Aβ(11-25) [7] and Ac-Aβ(16-22)-NH2 [8] form different anti-parallel β-sheet structures, which were previously identified β-NH2 [8] form different anti-parallel β-sheet structures, which were previously identified by 13C multiple-quantum and 13C{15N} REDOR solid-state NMR. In our unpublished work presented here it was found that 17O NMR chemical shifts are sensitive to the type of the secondary structure, i. e. a parallel vs. an anti-parallel β-sheet structures, while the quadrupolar parameters of 17O nuclei unexpectedly do not vary beyond the error limits in the simulated lineshapes of both fibrillized and unfibrillized peptide systems. Results of more advanced solidstate NMR techniques to measure heteronuclear distances, 15N{17O}-REAPDOR, 15N{17O}-TRAPDOR and 17O{15N}-REDOR on selectively 17O-Val18 and 15N-Phe20 labeled Ac-Aβ(16-22)-NH2 fibrils will be also discussed. These novel solid-state NMR experiments will provide additional tools for measuring hydrogen bonding in different secondary structures of peptides in amyloid fibrils.[1.] O.N.Antzutkin, Magn. Reson. Chem. 42 (2004) 231-246; [2.] A.Petkova et al. Science 307 (2005) 262-265; [3.] G.J.J.Stege, et al. Biochem. Biophys. Res. Comm., 262 (1999) 152-156;[4.] R.Kayed et al. Science, 300 (2003) 486-489; [5.] M.Bokvist, et al. J. Mol. Biol. 335 (2004) 1039-1049; [6.] O.N. Antzutkin, et al. Proc. Nat. Acad. Sci, U.S.A., 97 (2000) 13045-13050;[7.] A.T. Petkova, et al. J. Mol. Biol., 335 (2004) 247-260;[8.] J.J. Balbach, Y. (2000) 13045-13050; [9] A.T. Petkova, (2004) 247-260; [10] J.J. Balbach, Y.Ishii, O.N. Antzutkin, et al. Biochemistry 39 (2000) 13748-13759.
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- Filippov, Andrei, et al.
(author)
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Aggregation on an amyloid peptide as studied by NMR diffusometry and 2D NMR noesy spectroscopy
- 2009
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In: Protein folds in infectious and neurodegenerative diseases. - : Centre National de la Recherche Scientifique, CNRS. ; , s. 91-
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Conference paper (other academic/artistic)abstract
- Alzheimer's disease is a progressive neurodegenerative disorder affecting millions of people world-wide. Alzheimer's amyloid-b peptide forms amorphous aggregates or amyloid fibrils. However, recent studies indicate that soluble oligomers instead of fibrils may form probably most neurotoxic species. These oligomeric aggregates are difficult to study by traditional structural experimental techniques. NMR diffusometry offer useful additional possibilities. In freshly-prepared solutions (without any pre-aggregates of the peptide) diffusion of the peptide can often be described by an unique diffusion kinetics, which corresponds to the calculated diffusion coefficient of the amyloid- b peptide monomers with the Stokes-Einstein hard-sphere approximation (typically D ~10-10 m2/s). In a quasi-equilibrium or in pulse-induced conditions, new larger aggregates of Ab with diffusion coefficients down to <1×10-13 m2/s were detected. 2D 1H NMR NOESY provides both an additional evidence of aggregation and also reveals most probable sites of the side chain interactions in the aggregates. "Pulse-like" treatment of the sample involves: (i) changing of the solution composition; (ii) freezing-thawing; and (iii) sonication of the sample in the course of its incubation. Putative aggregation mechanisms and structures of monomers and oligomers in solutions at different conditions are discussed.1. Filippov A., Sulejmanova A., Antzutkin O. and Gröbner G. (2005) Diffusion and aggregation of Alzheimer's Abeta(1-40)-peptide in aqueous-TFE solutions as studied by pulsed field gradient NMR. Applied Magnetic Resonance. 29. 439 - 449.2. Filippov A., Sulejmanova A., Gröbner G. and Antzutkin O. (2008) Effect of freezing on amyloid peptide aggregation and self-diffusion in an aqueous solution. Colloid J. 70. 501-506.3. Filippov A., Gröbner G. and Antzutkin O. Effect of ultrasonication on amyloid peptide aggregation in trifluoroethanol solution. (in preparation).
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