scholarly journals Position dependence of the 13C chemical shifts of α-helical model peptides. Fingerprint of the 20 naturally occurring amino acids

2008 ◽  
Vol 13 (11) ◽  
pp. 2939-2948 ◽  
Author(s):  
Jorge A. Vila ◽  
Héctor A. Baldoni ◽  
Harold A. Scheraga
Keyword(s):  
Amino Acids ◽  
Chemical Shifts ◽  
13C Chemical Shifts ◽  
Naturally Occurring ◽  
Position Dependence ◽  
Model Peptides

Cross-linking of amino acids by formaldehyde. 13C N.M.R. spectra of model compounds

1975 ◽  
Vol 28 (4) ◽  
pp. 917 ◽  
Author(s):  
MK Dewar ◽  
RB Johns ◽  
DP Kelly ◽  
JF Yates
Keyword(s):  
Amino Acids ◽  
Chemical Shifts ◽  
Cross Linking ◽  
Model Compounds ◽  
13C Chemical Shifts

The use of 13C N.M.R. for the identification of the site of cross- linking of amino acids by formaldehyde has been evaluated by use of model compounds, such as 2,4-dimethylphenol for tyrosine. The 13C chemical shifts of the formaldehyde-derived methylene carbons occur within the range 50-60 p.p.m. downfield from Me4Si. Estimated shifts in lysine-lysine and tyrosine-glutamine cross-linked systems fall just outside this region. The 13C spectra of a number of related phenols, amines and protected amino acids are also reported.

scholarly journals Pressure dependence of side chain 13C chemical shifts in model peptides Ac-Gly-Gly-Xxx-Ala-NH2

2017 ◽  
Vol 69 (2) ◽  
pp. 53-67 ◽  
Author(s):  
Markus Beck Erlach ◽  
Joerg Koehler ◽  
Edson Crusca ◽  
Claudia E. Munte ◽  
Masatsune Kainosho ◽  
...  
Keyword(s):  
Pressure Dependence ◽  
Chemical Shifts ◽  
Side Chain ◽  
13C Chemical Shifts ◽  
Model Peptides

scholarly journals Real-time prediction of 1H and 13C chemical shifts with DFT accuracy using a 3D graph neural network

2021 ◽  
Author(s):  
Yanfei Guan ◽  
S. V. Shree Sowndarya ◽  
Liliana C. Gallegos ◽  
Peter C. St. John ◽  
Robert S. Paton
Keyword(s):  
Neural Network ◽  
Real Time ◽  
Quantum Chemical ◽  
Organic Molecules ◽  
Chemical Shifts ◽  
13C Chemical Shifts ◽  
Time Prediction ◽  
Nmr Data ◽  
Proton Chemical Shifts

From quantum chemical and experimental NMR data, a 3D graph neural network, CASCADE, has been developed to predict carbon and proton chemical shifts. Stereoisomers and conformers of organic molecules can be correctly distinguished.

scholarly journals Resolving Entangled JH-H-Coupling Patterns for Steroidal Structure Determinations by NMR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2643
Author(s):  
Danni Wu ◽  
Kathleen Joyce Carillo ◽  
Jiun-Jie Shie ◽  
Steve S.-F. Yu ◽  
Der-Lii M. Tzou
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr Spectroscopy ◽  
Chemical Shifts ◽  
Atomic Level ◽  
Molecular Structures ◽  
Naturally Occurring ◽  
Structure Determinations ◽  
Ligand Interactions ◽  
Synthetic Steroids ◽  
The Individual

For decades, high-resolution 1H NMR spectroscopy has been routinely utilized to analyze both naturally occurring steroid hormones and synthetic steroids, which play important roles in regulating physiological functions in humans. Because the 1H signals are inevitably superimposed and entangled with various JH–H splitting patterns, such that the individual 1H chemical shift and associated JH–H coupling identities are hardly resolved. Given this, applications of thess information for elucidating steroidal molecular structures and steroid/ligand interactions at the atomic level were largely restricted. To overcome, we devoted to unraveling the entangled JH–H splitting patterns of two similar steroidal compounds having fully unsaturated protons, i.e., androstanolone and epiandrosterone (denoted as 1 and 2, respectively), in which only hydroxyl and ketone substituents attached to C3 and C17 were interchanged. Here we demonstrated that the JH–H values deduced from 1 and 2 are universal and applicable to other steroids, such as testosterone, 3β, 21-dihydroxygregna-5-en-20-one, prednisolone, and estradiol. On the other hand, the 1H chemical shifts may deviate substantially from sample to sample. In this communication, we propose a simple but novel scheme for resolving the complicate JH–H splitting patterns and 1H chemical shifts, aiming for steroidal structure determinations.

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