Long-range 15N-1H correlation experiments for histidine rings
2D [15N, 1H] long-range HSQC for His rings
File:GNfhsqc His.tgz: long range 15N-1H HSQC package - tested with VnmrJ 2.1B
This pulse sequence correlates aromatic H-C protons of His with ring nitrogens. Modified from BioPack gNfhsqc.c by adding 90-180-90 composite 180 pulses on 15N and changing decoupling options.
- Save the gNfhsqc_His.tgz file into VnmrJ user home directory (e.g. /home/vnmr1).
- Extract with tar xvzf gNfhsqc_His.tar - existing files will be overwritten!
- JNH=22.75 Hz, to refocus 1J_NH couplings
- 15N carrier at 200 ppm
- 15N spectral width is 200 ppm
- 13C carrier at 125 ppm
- 15N decoupling during acquisition is off
- 13C 40 ppm WURST decoupling during acquisition
- 3-9-19 for water suppression
Points to consider:
- WURST decoupling produces strong side-bands, especially harmful if your protein has a His-tag. It is thus recommended to set 13C decoupling to GARP.
- On some instruments 90-180-90 composite 15N pulses may be longer than the corresponding 3-9-19 delay, creating a negative delay in the pulse sequence (look for the '?' in 'dps'). In this case use traditional WATERGATE instead of 3-9-19
There is also the rna_WGgNhsqclr setup macro from BioPack. This macro loads the rna_WGgNhsqc.c pulsesequece with parameters for long-range correlations.