600 400 200 0-200 -400 M 0 M 0
D D = kt/6a 2 d /2D a d a For sucrose/h 2O, we have D = 0.521X10-5 cm 2-1 s, then -13 d = 1 nm -11 d = 10 nm NMR frequency ~ 10 8 Hz All spin interactions become isotropic in solution, so how it can be used for structural determination?
300 200 100 0 200 100 0-100 600 400 200 0-200 -400 Chemical Shift/ppm
B 0 54.7 8 khz 4 khz Z 2 khz X Y 0 khz (static) 300 250 200 150 100 50 0-50 -100 Chemical Shift/ppm
600 400 200 0-200 -400 Chemical Shift/ppm 200 100 0-100 300 200 100 0
CSA Dipolar HI I HdI I I -I One-point sampling CSA I -I I -I I -I Dipolar I I
a) Insertion mechanism : C enriched 99.9% Ph Ph Rh Ph Ph Rh Ph Ph Ph b) Metathesis mechanism Ph Ph Ph Rh Rh Rh Ph Ph Ph
13 C dipolar powder pattern Rc- c = 0.1386 ± 0.0009 nm ref. (polyacetylene, 77K) C- C = 0.148 nm C=C = 0.136 nm The mechanism is the insertion mechanism!
CSA Dipolar HI I HdI I CSA d 0
Z Dipolar HdI I β X α Y Z 120 o HdI I X Y HtdtI I t=0 t = 1 rotational period dt
HtdtI I rf irradiation applied synchronously to modulate the spin part t t t=0 t = 1 cycle Ht t=0 t = 1 cycle Ht
(a) conventional CPMAS 13 C CP (b) MORE experimental 15 N + - + - + (c) MORE simulation 800 400 0-400 - 800 Hz 13 15 [2- C, N] glycine
Decoupling by MAS
Uniform Labeling by 13 C / 15 N Uniform Decoupling by MAS Selective Recoupling by R2TR
G 180 o 180 o I I I 1 I 2-76 144 179 160 o o o o G 165 o 170 o I I I 1 I 2-70 153 178 170 o o o o J. Biomol. NMR, 17 (2000) 111.
1 H CP Decouple Decouple 13 C t 1 t 2
Amyloid-β fibrils is related to Altzheimer's disease. These depositions are composed of amyloid-β peptides of 40- and 42-residues. 13 13 Assignment of C signals of C-labeled 21-24 aa by DARR with the mixing time of 20ms Aggrigative ability of these peptides relate to the 3D structures. Asp1-γ Asp2-γ Ala-CO Lys-CO Val1,2-CO Asp1-α Lys-α Asp2-α Val1,2-α Val2-β Val1-β Val2-γ Val1-γ Lys-β Asp1-β Asp2-β Lys-ε Ala -α Lys-γ Lys-δ Ala-β The Irie's model of amyloid- (Italian) 184 180 176 172 168 60 40 20 42 39 or 40 32 β-sheet β-sheet 24 20 15 β-sheet 21 40 60 184 180 Chemical 176 Shift/ppm 172 168 60 Chemical 40 Shift/ppm 20
DARR (mixing time=1 s) 160 120 80 40 Chemical Shift/ppm 40 80 120 160 Chemical Shift/ppm 20 30 40 50 Chemical Shift/ppm Ala Lys Asp Val If 21-24 residue is β-sheet, the side chains of Lys and Asp are too far. 60 180 176 172 Chemical Shift/ppm 21 Ala 22 Lys 23 Asp 24 Val NH C αh CO NH C αh CO NH C αh CO NH C αh CO CH3 C βh 2 C H (b) β 2 C βh C γh 2 (C) C γooh H 3 Cγ C γh 3 Ala Val Lys Asp C δh 2 C εh 2 N ζh 2 (a)
UV?
4 -ln((1-m(t))/2) 3 2 1 0 0 50 100 150 200 250 300
K/s -1 2.0 1.5 >1 s -1 1.0 0.5 0.06 0.04 0.02 0.0 0.5 1.0 Fraction of dimer f D
29 Si Q3 Q4 11.7 T -70-80 -90-100 -110-120 -130-140 -150 23 Na Na (aq) + Na + (solvated) 21.8 T H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr MnFe Co Ni Cu ZnGaGe As Se Br Kr RbSr Y Zr NbMoTc RuRhPdAgCd In Sn SbTe I Xe Cs Ba La Hf Ta W ReOs Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Ku Ha La Ce Pr NdPmSmEuGdTbDyHo Er TmYbLu Ac Th Pa U NpPuAmCmBk Cf Es FmMdNo Lr 30 20 10 0-10 -20-30 -40-50 27 Al four-coordinated 21.8 T 90 80 70 60 50 40 30 20 11 B 30 20 10 0-1 Chemical shift / ppm 21.8 T
H O B1 O O H O B2 O B2 O H O B1 O O H * MAS 2- B2 B1 120 60 0-60 -120 11 B * /ppm e 2 qq/h (MHz) 10 B B1 1.042 0.711 B2 5.4 0.10 11 B B1 0.487 0.714 B2 2.544 0.089 10B: Izv. Vyssh. Uchebn. Zaved. Fiz. 29, 3 (1986) 11B: J Chem. Phys., 38, 1912 (1963) B2 B1 11 B(I=3/2) 10 B 20 0-20 Chemical shift / ppm
Static B2 B1 MAS 120 60 0-60 -120 * /ppm 100 50 0-50 -100-150 Chemical Shift/ppm -200 30 20 10 0 10 MQMAS B1 B2 Either use higher magnetic field or do 2D-MQMAS! 30 20 10 0 10 Chemical shift/ppm
δiso / ppm e 2 Qqh -1 / MHz η 30.4 3.5 0.4 18.8 2.7 0.2 0.94 < 0.1 0 40 20 0-20 Chemical Sift (ppm) 40 20 0-20 Chemical Sift (ppm)
hbn cbn calc. ref. 1 calc. ref. 2 e 2 Qq / h 2.85 2.936-0.72 < 0.05 (MHz) η 0 0 0.01 0 1) Solid State NMR 12, 1-7 (1998) 2) Solid State NMR 8, 109-121 (1997)
30.0 20.0 10.0 0 site2 site3 This cross peak shows site2 and site1 30.0 20.0 10.0 0 Chemical shift / ppm M.Murakami et al., Solid State NMR, 2007 (31) 193.