| 1. |
- Antzutkin, Oleg, et al.
(författare)
-
Exploring solid-state 17O NMR to distinguish secondary structures in Alzheimer's Aβ fibrils
- 2009
-
Ingår i: Euromar 2009. ; , s. 107-
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)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 In our unpublished work presented here it was found that 17O NMR chemical shifts are sensitive to the type of the secondary structure, i. e. a parallel vs. an anti-parallel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.
|
|
| 2. |
|
|
| 3. |
- Antzutkin, Oleg, et al.
(författare)
-
Hydrogen bonding in Alzheimer’s amyloid-β fibrils probed by 15N{17O} REAPDOR solid-state NMR spectroscopy
- 2012
-
Ingår i: Angewandte Chemie. - : Wiley. - 0044-8249. ; 124:41, s. 10435-10438
-
Tidskriftsartikel (refereegranskat)abstract
- Nach selektiver Markierung mit 17O und 15N wurden mithilfe von 15N{17O}-REAPDOR-NMR-Spektroskopie intermolekulare C17O⋅⋅⋅H15N-Wasserstoffbrücken in Ac-Aβ(16–22)-NH2- (siehe Schema) und Aβ(11–25)-Amyloidfibrillen untersucht, die mit der Alzheimer-Krankheit in Verbindung gebracht werden. Die Methode, die eine Bestätigung für die Struktur dieser Fibrillen lieferte, könnte auch im Zusammenhang mit anderen biologischen Proben nützlich sein.
|
|
| 4. |
- Antzutkin, Oleg, et al.
(författare)
-
Hydrogen bonding in Alzheimer’s amyloid-β fibrils probed by 15N{17O} REAPDOR solid-state NMR spectroscopy
- 2012
-
Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 51:41, s. 10289-10292
-
Tidskriftsartikel (refereegranskat)abstract
- An exclusive label: 15N{17O} REAPDOR NMR was used to validate intermolecular C17O⋅⋅⋅H15N hydrogen bonding in Ac-Aβ(16–22)-NH2 (see scheme) and Aβ(11–25) amyloid fibrils, which are associated with Alzheimer’s disease, by selectively labeling them with 17O and 15N. This method was effective for confirming the structure of these fibrils, and could be useful for a number of other biological samples.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Rusanova, Daniela, et al.
(författare)
-
Formation of {Cu6[S2P(OC2H5)2]6} on Cu2S Surfaces from Aqueous Solutions of the KS2P(OC2H5)2 Collector: Scanning Electron Microscopy and Solid-State 31P Cross-Polarization/Magic Angle Spinning and Static 65Cu NMR Studies
- 2005
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 21:10, s. 4420-4424
-
Tidskriftsartikel (refereegranskat)abstract
- The interactions of synthetic chalcocite surfaces with diethyldithiophosphate, potassium salt, K[S2P(OC2H5)2], were studied by means of 31P cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy and scanning electron microscopy (SEM). To identify the species formed on the Cu2S surfaces, a polycrystalline {CuI6[S2P(OC2H5)2]6} cluster was synthesized and analyzed by SEM, powder X-ray diffraction techniques and solid-state 31P CP/MAS NMR and static 65Cu NMR spectroscopy. 31P chemical shift anisotropy (CSA) parameters, CS and CS, were estimated and used for assigning the bridging type of diethyldithiophosphate ligands in the {CuI6[S2P(OC2H5)2]6} cluster. The latter data were compared to 31P CSA parameters estimated from the spinning sideband patterns in 31P NMR spectra of the collector-treated mineral surfaces: formation of polycrystalline {CuI6[S2P(OC2H5)2]6} on the Cu2S surfaces is suggested. The second-order quadrupolar line shape of 65Cu was simulated, and the NMR interaction parameters, CQ and Q, for the copper(I) diethyldithiophosphate cluster were obtained.
|
|
| 8. |
- Rusanova, Daniela, et al.
(författare)
-
Solid-state 31P CP/MAS and static 65Cu NMR characterization of polycrystalline copper(I) dialkyldithiophosphate clusters
- 2006
-
Ingår i: Journal of magnetic resonance. - : Elsevier BV. - 1090-7807 .- 1096-0856. ; 179:1, s. 140-145
-
Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline tetra-nuclear Cu4[S2P(O-i-C3H7)2]4, hexa-nuclear Cu6[S2P(OC2H5)2]6, and octa-nuclear Cu8[S2P(O-i-C4H9)2]6(S) complexes were synthesized and analyzed by means of solid-state 31P CP/MAS and 65Cu static NMR spectroscopy. The symmetries of the electronic environments around each P-site were estimated from the 31P chemical shift anisotropy (CSA) parameters, Δaniso and η. The 65Cu chemical shift and quadrupolar splitting parameters obtained from the experimental 65Cu NMR spectra of the polycrystalline CuI-complexes are presented. A solid-state NMR approach for the elucidation of the stereochemistry of poly-nuclear Cu(I) dithiophosphate complexes, when the structural analysis of the systems by single-crystal X-ray diffraction is not readily available, is proposed.
|
|
| 9. |
- Rusanova, Daniela, et al.
(författare)
-
Solid-state NMR and EXAFS spectroscopic characterization of infoPolycrystalline copper(I) O,O prime -Dialkvldithiophosphate cluster compounds : Formation of copper(I) O,O prime -diisobutyklithiophosphate compounds on the surface of synthetic chalcocite
- 2006
-
Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 12:20, s. 5282-5292
-
Tidskriftsartikel (refereegranskat)abstract
- A number of polycrystalline copper(I) O,O-dialkyldithiophosphate cluster compounds with Cu4, Cu6, and Cu8 cores were synthesized and characterized by using extended X-ray absorption fine-structure (EXAFS) spectroscopy. The structural relationship of these compounds is discussed. The polycrystalline copper(I) O,O-diisobutyldithiophosphate cluster compounds, [Cu8{S2P(OiBu)2}6(S)] and [Cu6{S2P(OiBu)2}6], were also characterized by using 31P CP/MAS NMR (CP = cross polarization, MAS = magic-angle spinning) and static 65Cu NMR spectroscopies (at different magnetic fields) and powder X-ray diffraction (XRD) analysis. Comparative analyses of the 31P chemical-shift tensor, and the 65Cu chemical shift and quadrupolar-splitting parameters, estimated from the experimental NMR spectra of the polycrystalline copper(I) cluster compounds, are presented. The adsorption mechanism of the potassium O,O-diisobutyldithiophosphate collector, K[S2P(OiBu)2], at the surface of synthetic chalcocite (Cu2S) was studied by means of solid-state 31P CP/MAS NMR spectroscopy and scanning electron microscopy (SEM). 31P NMR resonance lines from collector-treated chalcocite surfaces were assigned to a mixture of [Cu8{S2P(OiBu)2}6(S)] and [Cu6{S2P(OiBu)2}6] compounds.
|
|
| 10. |
- Rusanova, Daniela, et al.
(författare)
-
Solid-state static 65Cu and 31P CP/MAS NMR, and liquid-state EXAFS studies on copper(I) O,O′-dialkyldithiophosphate cluster compounds : formation of the copper(I) O,O′-di-iso-amyldithiophosphate cluster compound on the surface of synthetic chalcocite
- 2006
-
Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 25:18, s. 3569-3580
-
Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline octa-nuclear copper(I) O,O′-di-i-propyl- and O,O′-di-i-amyldithiophosphate cluster compounds, {Cu8[S2P(OR)2]6(μ8-S)} where R = iPr and iAm, were synthesized and characterized by 31P CP/MAS NMR at 8.46 T and static 65Cu NMR at multiple magnetic field strengths (7.05, 9.4 and 14.1 T). The symmetries of the electronic environments around the P sites were estimated from the 31P chemical shift anisotropy (CSA) parameters, δaniso and η. Analyses of the 65Cu chemical shift and quadrupolar splitting parameters for these compounds are presented with the data being compared to those for the analogous octa-nuclear cluster compounds with R = nBu and iBu. The 65Cu transverse relaxation for the copper sites in {Cu8[S2P(OiPr)2]6(μ8-S)} and {Cu8[S2P(OiAm)2]6(μ8-S)} was found to be very different, with a relaxation time, T2, of 590 μs (Gaussian) and 90 μs (exponential), respectively. The structures of {Cu4[S2P(OiPr)2]4} and {Cu8[S2P(OiPr)2]6(μ8-S)} cluster compounds in the liquid- and the solid-state were studied by Cu K-edge EXAFS. The disulfide, [S2P(OiAm)2]2, was obtained and characterized by 31P{1H} NMR. The interactions of the disulfide and of the potassium O,O′-di-i-amyldithiophosphate salt with the surfaces of synthetic chalcocite (Cu2S) were probed using solid-state 31P NMR spectroscopy and only the presence of copper(I) dithiophosphate species with the {Cu8[S2P(OiAm)2]6(μ8-S)} structure was observed.
|
|
| 11. |
- Rusanova, Daniela, et al.
(författare)
-
Spectroscopic characterization of the polycrystalline copper(I) di-n-butyldithiophosphate cluster - Cu8[S2P(O-n-Bu)2]6(μ8-S): Solid-state 31P CP/MAS and static 65Cu NMR studies
- 2006
-
Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693 .- 1873-3255. ; 259:12, s. 3903-3910
-
Tidskriftsartikel (refereegranskat)abstract
- A polycrystalline copper(I) O,O′-di-n-butyldithiophosphate cluster compound, Cu8[S2P(O-n-Bu)2]6(μ8-S), was synthesized and characterized by 31P CP/MAS NMR at 8.46 T and static 65Cu NMR at multiple magnetic field strengths (7.05, 9.4 and 14.1 T). The principal values of the 31P chemical shift tensor and the 65Cu chemical shift and quadrupolar splitting parameters are presented. The data are compared to those for the analogous octa-nuclear cluster compounds [Cu8(S2P(OEt)2)6(μ8-S)], [Cu8(S2P(O-n-Pr)2)6(μ8-S)] and [Cu8(S2P(O-i-Bu)2)6(μ8-S)]. The transverse relaxation time constant, T2, for the [Cu8(S2P(O-n-Bu)2)6(μ8-S)] cluster compound was found to be 160 ± 8 μs. Possible intra-molecular motions in the cluster structures in terms of size and branching of the hydrocarbon chains are discussed as reasons for the different 65Cu NMR responses of the systems.
|
|
| 12. |
- Wei, Juan, et al.
(författare)
-
Amyloid Hydrogen Bonding Polymorphism Evaluated by 15N{17O}REAPDOR Solid-State NMR and Ultra-High Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry
- 2016
-
Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 55:14, s. 2065-2068
-
Tidskriftsartikel (refereegranskat)abstract
- A combined approach, using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and solid-state NMR (Nuclear Magnetic Resonance), shows a high degree of polymorphism exhibited by Aβ species in forming hydrogen-bonded networks. Two Alzheimer’s Aβ peptides, Ac-Aβ16–22-NH2 and Aβ11–25, selectively labeled with 17O and 15N at specific amino acid residues were investigated. The total amount of peptides labeled with 17O as measured by FTICR-MS enabled the interpretation of dephasing observed in 15N{17O}REAPDOR solid-state NMR experiments. Specifically, about one-third of the Aβ peptides were found to be involved in the formation of a specific >C═17O···H–15N hydrogen bond with their neighbor peptide molecules, and we hypothesize that the rest of the molecules undergo ± n off-registry shifts in their hydrogen bonding networks.
|
|
