title: Dynamic nuclear polarization-enhanced 13C NMR spectroscopy of static biological solids.
abstract: We explore the possibility of using dynamic nuclear polarization (DNP) to enhance signals in structural studies of biological solids by solid state NMR without sample spinning. Specifically, we use 2D (13)C-(13)C exchange spectroscopy to probe the peptide backbone torsion angles (φ, ψ) in a series of selectively (13)C-labeled 40-residue β-amyloid (Aβ(1-40)) samples, in both fibrillar and non-fibrillar states. Experiments are carried out at 9.39 T and 8 K, using a static double-resonance NMR probe and low-power microwave irradiation at 264 GHz. In frozen solutions of Aβ(1-40) fibrils doped with DOTOPA-TEMPO, we observe DNP signal enhancement factors of 16-21. We show that the orientation- and frequency-dependent spin polarization exchange between sequential backbone carbonyl (13)C labels can be simulated accurately using a simple expression for the exchange rate, after experimentally determined homogeneous (13)C lineshapes are incorporated in the simulations. The experimental 2D (13)C-(13)C exchange spectra place constraints on the φ and ψ angles between the two carbonyl labels. Although the data are not sufficient to determine φ and ψ uniquely, the data do provide non-trivial constraints that could be included in structure calculations. With DNP at low temperatures, 2D (13)C-(13)C exchange spectra can be obtained from a 3.5 mg sample of Aβ(1-40) fibrils in 4 h or less, despite the broad (13)C chemical shift anisotropy line shapes that are observed in static samples.
authors.affiliation: Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA. alexey.potapov@nih.gov
authors.forename: Alexey
authors.initials: A
authors.lastname: Potapov
authors.forename: Wai-Ming
authors.initials: WM
authors.lastname: Yau
authors.forename: Robert
authors.initials: R
authors.lastname: Tycko
mesh_terms: D016229:Amyloid beta-Peptides / Q000032:analysis* / Q000737:chemistry*; D001704:Biopolymers / Q000032:analysis* / Q000737:chemistry*; D002247:Carbon Isotopes / Q000032:analysis / Q000737:chemistry; D005240:Feasibility Studies; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010446:Peptide Fragments / Q000032:analysis* / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D016229:Amyloid beta-Peptides; D001704:Biopolymers; D002247:Carbon Isotopes; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40)
references.citation: J Magn Reson. 2010 Jun;204(2):303-13
references.pmid: 20392658
references.citation: Annu Rev Phys Chem. 2008;59:635-57
references.pmid: 18393681
references.citation: J Magn Reson. 2012 Nov;224:13-21
references.pmid: 23000976
references.citation: J Am Chem Soc. 2011 Feb 23;133(7):2104-7
references.pmid: 21280606
references.citation: Proc Natl Acad Sci U S A. 2009 Aug 11;106(32):13311-6
references.pmid: 19633188
references.citation: Proc Natl Acad Sci U S A. 2003 Sep 2;100(18):10158-63
references.pmid: 12930897
references.citation: Angew Chem Int Ed Engl. 2011 Aug 29;50(36):8367-70
references.pmid: 21770004
references.citation: J Am Chem Soc. 2011 Oct 12;133(40):16013-22
references.pmid: 21882806
references.citation: Proc Natl Acad Sci U S A. 2008 Nov 25;105(47):18349-54
references.pmid: 19015532
references.citation: J Am Chem Soc. 2007 May 2;129(17):5318-9
references.pmid: 17425317
references.citation: Phys Chem Chem Phys. 2010 Jun 14;12(22):5883-92
references.pmid: 20458428
references.citation: Proc Natl Acad Sci U S A. 2002 Aug 6;99(16):10266-71
references.pmid: 12149440
references.citation: Science. 1998 May 1;280(5364):714-7
references.pmid: 9563942
references.citation: Proc Natl Acad Sci U S A. 2002 Dec 24;99(26):16742-7
references.pmid: 12481027
references.citation: J Magn Reson. 2006 Jan;178(1):106-20
references.pmid: 16243550
references.citation: Proc Natl Acad Sci U S A. 2009 Jun 9;106(23):9244-9
references.pmid: 19474298
references.citation: Phys Chem Chem Phys. 2010 Jun 14;12(22):5911-9
references.pmid: 20454733
references.citation: J Mol Biol. 2009 Oct 2;392(4):1055-73
references.pmid: 19647001
references.citation: J Magn Reson. 2012 Aug;221:5-10
references.pmid: 22743536
references.citation: J Am Chem Soc. 2010 Nov 10;132(44):15459-61
references.pmid: 20831165
references.citation: J Magn Reson. 2007 Dec;189(2):251-79
references.pmid: 17942352
references.citation: Phys Chem Chem Phys. 2010 Jun 14;12(22):5850-60
references.pmid: 20449524
references.citation: Chemphyschem. 2011 Nov 18;12(16):2929-32
references.pmid: 22028312
references.citation: J Am Chem Soc. 2006 Sep 6;128(35):11385-90
references.pmid: 16939261
references.citation: Annu Rev Biophys Biomol Struct. 1999;28:235-68
references.pmid: 10410802
references.citation: J Am Chem Soc. 2011 Dec 7;133(48):19266-9
references.pmid: 22039931
references.citation: J Magn Reson. 2012 Aug;221:32-40
references.pmid: 22743540
references.citation: Phys Chem Chem Phys. 2010 Jun 14;12(22):5779-85
references.pmid: 20458431
references.citation: J Am Chem Soc. 2011 Dec 21;133(50):20208-17
references.pmid: 21854063
references.citation: J Am Chem Soc. 2006 Aug 23;128(33):10840-6
references.pmid: 16910679
references.citation: J Chem Phys. 2012 Aug 28;137(8):084508
references.pmid: 22938251
references.citation: J Magn Reson. 2007 Aug;187(2):266-76
references.pmid: 17560151
references.citation: Proc Natl Acad Sci U S A. 2008 Jan 22;105(3):883-8
references.pmid: 18195364
references.citation: Proc Natl Acad Sci U S A. 2000 Nov 21;97(24):13045-50
references.pmid: 11069287
references.citation: Angew Chem Int Ed Engl. 2012 Jan 9;51(2):432-5
references.pmid: 22113890
references.citation: Chem Commun (Camb). 2012 Feb 14;48(14):1988-90
references.pmid: 22237253
references.citation: Chem Rev. 2004 Aug;104(8):3587-606
references.pmid: 15303829
references.citation: J Am Chem Soc. 2011 Nov 30;133(47):19084-6
references.pmid: 22040139
references.citation: J Am Chem Soc. 2010 May 5;132(17):5940-1
references.pmid: 20392100
references.citation: J Chem Phys. 2011 Mar 28;134(12):125105
references.pmid: 21456705
references.citation: J Am Chem Soc. 2010 May 5;132(17):5993-6000
references.pmid: 20387894
references.citation: J Chem Phys. 2008 Feb 7;128(5):052302
references.pmid: 18266419
references.citation: J Biomol NMR. 2011 Jun;50(2):119-27
references.pmid: 21416162
references.citation: J Am Chem Soc. 2011 Sep 7;133(35):13967-74
references.pmid: 21774549