CONCA 3D

Experiment Details

Dimensions = 3

Isotope labeling required = ¹³C and ¹⁵N

Magnetization transfer = Establishes correlation between ¹³CO_i−1 to ¹³Cα_i and ¹⁵N_i with single quantum coherences evolving simultaneously on the CO_i, N_i

Magentization is generated on ¹H and transferred to ¹³C via CP. ¹³C chemical shift evolves during t1. Band selective ¹³CO_i-1 to ¹⁵N_i is obtained via spin lock on ¹⁵N and ramping through the specific CP matching on the ¹³C channel. The magentization then evolves on ¹⁵N during t2 followed by transfer to ¹³Cα_i and detection.

Pulse program:

2001, Griffin et. al.

Comment on key optimization:

ZGOPTNS = '-Dnomix';cnst22 = '55'; cnst21 = '175; p2 = 2*p1; p22 = 2*p21;

parmode = 3D; o1p = '100'; o2p = '3'; o3p = '115'; ZGOPTNS = '-DCDC' for constant duty cycle

Example spectrum (20011, Griffin et.al): The 3D spectrum correlates the ( ¹³CO _i−1 ) to ( ¹⁵N _i ) and ( ¹³Cα _i ) when t1 and t2 are incremented independently.

Left figure: Contour plot of a sample of peptide U-[ 15 N, 13 C]-N-Acetyl-Valine-Leucine (VL) acquired with t 2 = 0. ω 1 =( ¹⁵ N _i ) and ω 3 = ( ¹³ Cα _i )-the valine at ω 1 = 123.9 ppm, ω 3 = 58.7 ppm and the leucine at ω 1 = 129.1, ω 3 = 57.1 ppm.

Right figure:Same expt with simultaneous incrementation of t1 and t2 evolution periods. The peaks split into doublet centered in ¹⁵N_i

References:

1. R. Griffin (2001) JMR, 8, vol. 152, 303-307.

2. Y. Li, D.A. Berthold, H.L. Frericks, R.B. Gennis, C.M. Rienstra (2007) Chem. Biochem. 8 434-442.

3. Lichi Shi, Mumdooh A.M. Ahmed, Wurong Zhang, Gregg Whited, Leonid S. Brown, Vladimir Ladizhansky, T. Journal of Molecular Biology, Volume 386, Issue 4, 2009, Pages 1078-1093.