Dipolar-Chemical Shift and Rotational Resonance13C NMR Studies of the Carboxyl−Methylene Carbon Spin Pair in Solid Phenylacetic Acid and Potassium Hydrogen Bisphenylacetate

2000 ◽  
Vol 104 (32) ◽  
pp. 7700-7710 ◽  
Author(s):  
David L. Bryce ◽  
Roderick E. Wasylishen
Keyword(s):  
Chemical Shift ◽  
Phenylacetic Acid ◽  
Nmr Studies ◽  
Methylene Carbon ◽  
Spin Pair ◽  
Potassium Hydrogen

NMR studies of tandem WW domains of Nedd4 in complex with a PY motif-containing region of the epithelial sodium channel

1998 ◽  
Vol 76 (2-3) ◽  
pp. 341-350 ◽  
Author(s):  
Voula Kanelis ◽  
Neil A Farrow ◽  
Lewis E Kay ◽  
Daniela Rotin ◽  
Julie D Forman-Kay
Keyword(s):  
Chemical Shift ◽  
Sodium Channel ◽  
Chemical Shifts ◽  
Epithelial Sodium Channel ◽  
Chemical Shift Assignment ◽  
Nmr Studies ◽  
Ww Domains ◽  
Ww Ii ◽  
Py Motif ◽  
Shift Assignment

Nedd4 (neuronal precursor cell-expressed developmentally down-regulated 4) is a ubiquitin-protein ligase containing multiple WW domains. We have previously demonstrated the association between the WW domains of Nedd4 and PPxY (PY) motifs of the epithelial sodium channel (ENaC). In this paper, we report the assignment of backbone 1Hα, 1HN, 15N, 13C', 13Cα, and aliphatic 13C resonances of a fragment of rat Nedd4 (rNedd4) containing the two C-terminal WW domains, WW(II+III), complexed to a PY motif-containing peptide derived from the β subunit of rat ENaC, the βP2 peptide. The secondary structures of these two WW domains, determined from chemical shifts of 13Cα and 13Cβ resonances, are virtually identical to those of the WW domains of the Yes-associated protein YAP65 and the peptidyl-prolyl isomerase Pin1. Triple resonance experiments that detect the 1Hα chemical shift were necessary to complete the chemical shift assignment, owing to the large number of proline residues in this fragment of rNedd4. A new experiment, which correlates sequential residues via their 15N nuclei and also detects 1Hα chemical shifts, is introduced and its utility for the chemical shift assignment of sequential proline residues is discussed. Data collected on the WW(II+III)-βP2 complex indicate that these WW domains have different affinities for the βP2 peptide.Key words: WW domain, PY motif, Nedd4, ENaC, NMR.

Diyne Cyclization in Camphor Derivatives - Experimental and Theoretical Investigation

1996 ◽  
Vol 51 (11) ◽  
pp. 1655-1662 ◽  
Author(s):  
Gabriele Wagner ◽  
Christian Heiß ◽  
Uwe Verfiirth ◽  
Rudolf Herrmann
Keyword(s):  
Oxygen Atom ◽  
Theoretical Investigation ◽  
Positive Charge ◽  
Membered Ring ◽  
Titanium Chloride ◽  
Nmr Studies ◽  
Methylene Carbon ◽  
Camphor Derivatives ◽  
Exocyclic Methylene ◽  
Derivatives Of

Derivatives of 3-oxo-camphorsulfonimide (1) with two phenylethynyl groups in the endo positions at the carbons C-2 and C-3 were prepared, and their reactivity towards halogenes and titanium chloride was studied. In every case, the two ethynyl groups led to the annulation of a five-membered ring to the bicyclo[2 .2 .1] system in an orientation which depends on the bulkiness of the additional substituent in position 3. NMR studies show that cationic species like 6 and 8 are the first detectable intermediates. They not only contain the fused five-membered ring but also a bond between its exocyclic methylene carbon and an oxygen atom of the sulfonyl group, thus transferring the positive charge mainly to sulfur. Semiempirical calculations (PM3) suggest two intermediates in the formation of such cations.

13C NMR studies of conformational isomerism in thioureas: Signal assignments via chemical shift and population trends

1983 ◽  
Vol 21 (5) ◽  
pp. 293-300 ◽  
Author(s):  
Richard H. Sullivan ◽  
Pamela Nix ◽  
Eddie L. Summers Jun. ◽  
Stanley L. Parker
Keyword(s):  
Chemical Shift ◽  
13C Nmr ◽  
Population Trends ◽  
Conformational Isomerism ◽  
Nmr Studies
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