Selenocysteine is expected to have 92=81 conformations [in the backbone: y(g+,a,g-)¥f(g+,a,g-); 32=9 and in the sidechain: c1(g+,a,g-)¥c2(g+,a,g-); 32=9]. All torsional modes of the sidechain (c1: rotation about the Ca–Cb and c2: rotation about the Cb–Se bonds) were investigated in the relaxed bl backbone [(y,f), (a,a)] conformation. The relaxed potential energy surface (PES) obtained at the RHF/3-21G level of theory contained seven out of nine possible minima of the sidechain. All minima were re-optimized at the RHF/6-31G(d) and the B3LYP/6-31G(d) levels of theory. Two of the minima (g+a) and (g-g+) located at RHF/3-21G level of theory were annihilated when optimized at higher levels of theory. The frequency calculations for the found minima were used to construct the thermodynamic functions. The relative energies of the –CH2–SeH sidechain conformations have been compared with the relative energies of the analogous –CH2–SH and –CH2–OH sidechain conformers. Oxidative dimerization energies were also estimated.

Selenocysteine derivatives I. Sidechain conformational potential energy surface of N-acetyl-L-selenocysteine-N-methylamide (MeCO-L-Sec-NH-Me) in its betaL backbone conformation

BOTTONI, ANDREA
2005

Abstract

Selenocysteine is expected to have 92=81 conformations [in the backbone: y(g+,a,g-)¥f(g+,a,g-); 32=9 and in the sidechain: c1(g+,a,g-)¥c2(g+,a,g-); 32=9]. All torsional modes of the sidechain (c1: rotation about the Ca–Cb and c2: rotation about the Cb–Se bonds) were investigated in the relaxed bl backbone [(y,f), (a,a)] conformation. The relaxed potential energy surface (PES) obtained at the RHF/3-21G level of theory contained seven out of nine possible minima of the sidechain. All minima were re-optimized at the RHF/6-31G(d) and the B3LYP/6-31G(d) levels of theory. Two of the minima (g+a) and (g-g+) located at RHF/3-21G level of theory were annihilated when optimized at higher levels of theory. The frequency calculations for the found minima were used to construct the thermodynamic functions. The relative energies of the –CH2–SeH sidechain conformations have been compared with the relative energies of the analogous –CH2–SH and –CH2–OH sidechain conformers. Oxidative dimerization energies were also estimated.
2005
I.L.Hegedus; M.A.Sahai; M.Labadi; M.Szory; G.Paragi; B. Viskolcz; A.Bottoni
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/12912
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 5
social impact