Theoretical investigations of oxygen-17 NMR chemical shifts to discriminate among helical forms.
17O, 15N, 13C, and 1H NMR chemical shieldings are calculated using density functional theory to differentiate among the three primarily helical forms, 310, alpha, and pi in polyalanine peptides under periodic boundary conditions. This study suggests 17O as the best observable, as it has been demonstrated to be sensitive to hydrogen bonding and highly affected by small changes in the polypeptide in helix conformations. This theoretical study seeks to characterize the subtle conformational differences of helical structures by NMR chemical shift observables which may lead to important questions in experimental structure determination on the basis of using chemical shifts to identify protein secondary structures.
De Gortari
Itzam
I
TCM Group, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, United Kingdom. dego@nmr.mpibpc.mpg.de
Galván
Marcelo
M
Ireta
Joel
J
Segall
Matthew
M
Pickard
Chris J
CJ
Payne
Mike
M
D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D010103:Oxygen Isotopes / Q000737:chemistry*
D010103:Oxygen Isotopes