Conformational analysis of oxidized peptide fragments of the C-terminal redox center in thioredoxin reductases by NMR spectroscopy.

ABSTRACT: Vicinal disulfide rings (VDRs) occur when a disulfide bond forms between adjacent cysteine residues in a protein and results in a rare eight-membered ring structure. This eight-membered ring has been found to exist in four major conformations in solution, divided between cis and trans conformers. Some selenoenzymes use a special type of VDR in which selenium replaces sulfur, generating a vicinal selenosulfide ring (VSeSR). Here, we provide evidence that this substitution reduces ring strain, resulting in a strong preference for the trans conformation relative to cis in a VSeSR (cis:trans - 9:91). This was determined by using the 'γ-gauche effect', which makes use of both (1) H-NMR and two-dimensional (2D) NMR techniques for determining the amide bond conformeric ratio. The presence of sele

SUBMITTER: Ruggles EL 

PROVIDER: S-EPMC4000577 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature