1. FT NMR WORKSHOP/===/ S.A.I.F./===/ NEHU/==/ Shillong
FT NMR WORKSHOP/===/ S.A.I.F./===/ NEHU/==/ Shillong
INTRODUCTORY LECTURE
S.ARAVAMUDHAN

2. SDBS-13C NMR L-alanine Glycine
SDBS-13C NMR
L-alanylglycine

3. Proton NMR spectra also have similar trends
SDBS-13C NMR
glycylglycine
Glycine
Glycylglycylglycine
glycylglycylglycylglycine
Proton NMR spectra also have similar trends

5.
TEXT COPY
Bundi, A. and Wuthrich, K., "1H-NMR Parameters of the Common Amino Acid Residues Measured in Aqueous Solutions of the Linear Tetrapeptides H-Gly-Gly-X-L-Ala-OH," Biopolymers 18, (1979). ; 2 ;
Richarz, R. and Wuthrich, K., "Carbon-13 NMR Chemical Shifts of the Common Amino Acid Residues Measured in Aqueous Solutions of the Linear Tetrapeptides H-Gly-Gly-X-L-Ala-OH," Biopolymers 17, (1978). ; 3 ; Wuthrich, K. "NMR in Biological Research: Peptides and Proteins," North Holland, Amsterdam (1975).

6. The values have ben tabulated for all the 20 amino acids

7. Click HERE for copy

8. Similarly for all the 20 amino acids characteristics in NMR are enlisted

12. The fist step in sequential assignment is the identification of certain amino acids, with a characteristic pattern of cross signals, i.e. of glycine, alanine, threonine, valine, leucine and isoleucine.

13. double resonance The HSQC Experiment:
It correlates the nitrogen atom of an NHx group with the directly attached proton.
Each signal in a HSQC spectrum represents a proton that is bound to a nitrogen atom.

15. Thus, dipeptides are identified and subsequently prolonged to oligopeptides by the search for further sequential contacts. Some time along the line these oligopeptides can be placed at a unique place in the primary structure by comparison with the amino acid sequence of the protein - they are sequentially assigned.
The chain of sequential connectivites is interrupted by proline residues because these have no amide proton. Therefore, no HN(i)-Halpha(i-1) cross signal can be observed. However, if the proline (i) is in its trans conformation, the sequential HN(i-1)-Hdelta(i) and Halpha(i-1)-Hdelta(i) cross signals can be observed.
Another problem is, that this approach of sequential assignment breaks down for larger proteins because the vast number of signals leads to spectral overlap which hinders the identification of signals.

17. Organic Chemistry Info
Biomolecular Structure
Protein NMR - A Practical Guide
Assigned Chemical Shift Outliers for 'Diamagnetic' Proteins
data_Standard_amino_acid_chemical_shifts_pentapeptide_GGXGG_in_Urea
Bundi, A. and Wuthrich, K., "1H-NMR Parameters of the Common Amino Acid Residues Measured in Aqueous Solution
s of the Linear Tetrapeptides H-Gly-Gly-X-L-Ala-OH," Biopolymers 18, (1979).
Spectral Data Base: 1H, 13C, IR, Raman, Mass

18.
The Internet references are mainly to provide a quick reinforcement to the materials delivered at this woekshop, for an immediate follow up soon after the concluding session of the workshop.
The purpose should be to make use of the NMR technique with a better authenticity by acquring necessary copyright permissions and based on ones own experiences by gaining confidence by consulting the original publications of standrad authors by standard publications. Even such resources are available from the appropriate portals with proper registration and subscriptions.