3D HSQC-TOCSY-NOESY-HSQC NMR Experiment

From NMR Wiki

3D HSQC-TOCSY-NOESY-HSQC experiment [1] designed for ¹⁵N labeled proteins correlates chemical shifts of amide ¹⁵N with those of ¹H and ¹⁵N atoms of another amide group.

Coherence follows the following pathway: H¹⁵N -- inept --> H¹⁵N (ω1) -- TOCSY --> H_α -- NOE --> H¹⁵N -- inept --> H¹⁵N (ω2) -- inept --> H (ω3)¹⁵N

What experiment does: correlates ¹H (δ₃), ¹⁵N (δ₂) chemical shifts of amide group of one aminoacid residue (residue A) with ¹⁵N shift (δ₁) of another amide group (B) whose side chain (mostly Ha atom) is close in space to the amide ¹H atom of residue A.

Purpose of experiment: aid sequential assignment of resonances in samples with poor proton chemical shift dispersion.

Sample requirements: works best with β-sheet proteins where TOCSY transfer H-N-Ca-Ha is more efficient.

Pulse sequence entry incomplete....

References

1. Zhang, O and Kay, LE and Olivier, JP and Forman-Kay, JD. Backbone 1 H and 15 N resonance assignments of the N-terminal SH3 domain of drk in folded and unfolded states using enhanced-sensitivity pulsed field gradient NMR techniques. Journal of Biomolecular NMR 4(6):845--858, 1994. BibTeX [zhang94]