NOESY_Proteins_and_Carbs_10

NOESY_Proteins_and_Carbs_10 - / 12 = 0.25 , implies: r 14 =...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
NOESY – Applications to Proteins and Carbohydrates BCMB/CHEM 8190
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2D NOE Spectroscopy (NOESY) d1 (recover) t1 (evolve) t2 (observe) 90x 90x 90x mix x y z x y z ω a ω b x y z ω a ω b x y z x y z Some magnetization precessing at ω a in t1 can precess at ω b in t2
Background image of page 2
Periodic Inversion Sets Stage for Magnetization Transfer During Mixing Time T = 0 T = Δ T For short T, Large τ c , Δ I 1/r 6 Δ I 1 H 1 H r M
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
In Practice NOE depends on competition between W 0 and W 2 processes αβ ( δ ) βα ( δ ) ββ (0) αα (2 δ ) αβ ( δ /2) βα (3 δ /2) ββ ( δ /2) αα (3 δ /2) αβ ( δ /2+ Δ ) βα (3 δ /2- Δ ) ββ ( δ /2) αα (3 δ /2) irradiate relax, assuming W 0 dominates observe W 2 W 0 E
Background image of page 4
In Practice Data May be Collected for Cross Peaks at a Series of Mixing Times I cp = C{exp(- ρ T) • (1 – exp(-2 σ T)} ρ = 2W 1 + W 2 + W 0 , σ = (W 2 - W 0 ) T dI cp /dT 1/r 6 I cp
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
r 12 r 14’ NOEs Give Structural Information σ 14’ / σ 12 = r 12 6 / r 14’ 6 r 12 = 2.5 Å, σ 14’
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 10
Background image of page 11
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: / 12 = 0.25 , implies: r 14 = 3.15 Potential NOE Interactions In an Idealized -Helix NOESY Spectrum of ACP NOEs are Positive for Small Molecules, Negative for Large = (-1 + 6/(1+4 2 c 2 ))/(1 + 3/(1+ 2 c 2 ) + 6/(1+4 2 c 2 )) c 0 -1 1/2 1.1/ NOEs for Intermediate Sized Molecules: ROESY Short peptides and oligosaccharides often have tumbling times near 1/ , and NOEs near zero. ROESY Rotating Frame Overhauser Effect Spectroscopy offers a solution cross-relaxation in the low effective field of a spin-lock. Cross-peaks and auto-peaks are always of opposite sign. Still 1/r 6 dependent. the intensity for a large molecule. 90x m t1 t2 spin-lock Example of ROESY Galactose-pentaacetate H1 H4 H3 H2 H6 H5...
View Full Document

This note was uploaded on 11/07/2011 for the course CHEM 8853R taught by Professor Gelbaum during the Fall '11 term at Georgia Institute of Technology.

Page1 / 11

NOESY_Proteins_and_Carbs_10 - / 12 = 0.25 , implies: r 14 =...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online