Reactions of tert-butyl trimethylsilyl carbonate and of bistrialkylsilyl carbonates with amino acids. Carbon-13 chemical shifts in carbonates and silyl carbonate derivatives

1973 ◽  
Vol 38 (14) ◽  
pp. 2521-2525 ◽  
Author(s):  
Yutaka Yamamoto ◽  
D. Stanley Tarbell ◽  
James R. Fehlner ◽  
B. M. Pope
2017 ◽  
Vol 38 (30) ◽  
pp. 2605-2617 ◽  
Author(s):  
Jayangika N. Dahanayake ◽  
Chandana Kasireddy ◽  
Jonathan M. Ellis ◽  
Derek Hildebrandt ◽  
Olivia A. Hull ◽  
...  

1993 ◽  
Vol 34 (46) ◽  
pp. 7409-7412 ◽  
Author(s):  
Pierre Chevallet ◽  
Patrick Garrouste ◽  
Barbara Malawska ◽  
Jean Martinez

1999 ◽  
Vol 54 (3-4) ◽  
pp. 156-162 ◽  
Author(s):  
Jessica Voss ◽  
Kambiz Taraz ◽  
Herbert Budzikiewicz

From the strain 51W of Pseudomonas fluorescens living under extreme conditions at the Schirmacher Oasis (Antarctica) a pyoverdin was obtained. Its structure was elucidated by chemical degradation and spectroscopic methods. The NMR data of the pyoverdin and of its Ga(III) complex were compared. Appreciable influences of the metal on the chemical shifts of the atoms at its binding sites were observed. Thus the structural elements involved in the complexation can be identified and coinciding signals of amino acids occurring more than once in the peptide chain can be separated.


2020 ◽  
Vol 74 (8-9) ◽  
pp. 381-399
Author(s):  
Markus Beck Erlach ◽  
Joerg Koehler ◽  
Claudia E. Munte ◽  
Werner Kremer ◽  
Edson Crusca ◽  
...  

Abstract For interpreting the pressure induced shifts of resonance lines of folded as well as unfolded proteins the availability of data from well-defined model systems is indispensable. Here, we report the pressure dependence of 1H and 15N chemical shifts of the side chain atoms in the protected tetrapeptides Ac-Gly-Gly-Xxx-Ala-NH2 (Xxx is one of the 20 canonical amino acids) measured at 800 MHz proton frequency. As observed earlier for other nuclei the chemical shifts of the side chain nuclei have a nonlinear dependence on pressure in the range from 0.1 to 200 MPa. The pressure response is described by a second degree polynomial with the pressure coefficients B1 and B2 that are dependent on the atom type and type of amino acid studied. A number of resonances could be assigned stereospecifically including the 1H and 15N resonances of the guanidine group of arginine. In addition, stereoselectively isotope labeled SAIL amino acids were used to support the stereochemical assignments. The random-coil pressure coefficients are also dependent on the neighbor in the sequence as an analysis of the data shows. For Hα and HN correction factors for different amino acids were derived. In addition, a simple correction of compression effects in thermodynamic analysis of structural transitions in proteins was derived on the basis of random-coil pressure coefficients.


Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5495
Author(s):  
F. Teleanu ◽  
C. Tuță ◽  
A. Cucoanes ◽  
S. Vasilca ◽  
P. R. Vasos

Nuclear magnetization storage in biologically-relevant molecules opens new possibilities for the investigation of metabolic pathways, provided the lifetimes of magnetization are sufficiently long. Dissolution-dynamic nuclear polarization-based spin-order enhancement, sustained by long-lived states can measure the ratios between concentrations of endogenous molecules on a cellular pathway. These ratios can be used as meters of enzyme function. Biological states featuring intracellular amino-acid concentrations that are depleted or replenished in the course of in-cell or in-vivo tests of drugs or radiation treatments can be revealed. Progressing from already-established long-lived states, we investigated related spin order in the case of amino acids and other metabolites featuring networks of coupled spins counting up to eight nuclei. We detail a new integrated theoretical approach between quantum chemistry simulations, chemical shifts, J-couplings information from databanks, and spin dynamics calculations to deduce a priori magnetization lifetimes in biomarkers. The lifetimes of long-lived states for several amino acids were also measured experimentally in order to ascertain the approach. Experimental values were in fair agreement with the computed ones and prior data in the literature.


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