NMR Spectroscopy assignment
pin_gl
Amino Acid sequence of the peptide: G-I-G-A-V-L-K-V-L- A-L-I-S-W-I-K-R-K-R Clues: the cross-peak in TOCSY spectrum at 8.65 ppm and 3.89 ppm is a spin system of Lys. the cross-peak in TOCSY spectrum at 8.31 ppm and 4.10 ppm refers to spin systems of Leu/Ala, (Leu9 and one Ala (Ala4 or Ala10) have very close chemical shifts). the cross-peaks in TOCSY spectrum at 8.15 ppm and 4.00 ppm is a spin system of Lys the cross-peaks in TOCSY spectrum at 7.85 ppm and 4.33 ppm is a spin system of Leu Chemical Shift at 3.861/8.40 corresponds to G3
Question
1. Make sequence-specific resonance assignment. Mark the CαH/HN cross-peaks on the TOCSY finger print region.
2. Plot deviation of CαH chemical shifts from the random coil values (use the table for the random coil values).
3. Label the HN/HN NOESY cross-peaks in the NOESY spectrum.
4. Deduce the structure of the peptide. Provide reasons
Date of submission (hard copy): 7th April after the tutorial
TOCSY (HN to CαH and other aliphatic sidechain proton resonances) [mark sequence specific assignments on CαH/HN cross-peaks] [submit this spectrum]
Use these CαH chemical shifts for measuring deviation from the random coil values
2-D NOESY (HN to CαH and other aliphatic sidechain protons) [may be helpful for assignment work]
Overlay of the TOCSY and NOESY spectra (blue: TOCSY peaks and red: NOESY) [Use this to show sequential walk] [submit this spectrum]
NOESY between Amide-protons [Assign the HN/HN NOE connectivity and submit this spectrum]
Entire NOESY spectrum [For your reference]
Entire TOCSY spectrum (For your reference)
Part of the TOCSY spectrum showing correlation between the aliphatic protons (CαH to sidechains, sidechains to sidechains) [for your reference]