Optical spectroscopic elucidation of β-turns in disulfide bridged cyclic tetrapeptides

Attila Borics, Richard F. Murphy, Sándor Lovas

Research output: Contribution to journalArticle

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Abstract

Vibrational circular dichroism (VCD) spectroscopic features of type II β-turns were characterized previously, but, criteria for differentiation between β-turn types had not been established yet. Model tetrapeptides, cyclized through a disulfide bridge, were designed on the basis of previous experimental results and the observed incidence of amino acid residues in the i + 1 and i + 2 positions in β-turns, to determine the features of VCD spectra of type I and II β-turns. The results were correlated with electronic circular dichroism (ECD) spectra and VCD spectra calculated from conformational data obtained by molecular dynamics (MD) simulations. All cyclic tetrapeptides yielded VCD signals with a higher frequency negative and a lower frequency positive couplet with negative lobes overlapping. MD simulations confirmed the conformational homogeneity of these peptides in solution. Comparison with ECD spectroscopy, MD, and quantum chemical calculation results suggested that the low frequency component of VCD spectra originating from the tertiary amide vibrations could be used to distinguish between types of β-turn structures. On the basis of this observation, VCD spectroscopic features of type II and VIII β-turns and ECD spectroscopic properties of a type VIII β-turn were suggested. The need for independent experimental as well as theoretical investigations to obtain decisive conformational information was recognized.

Original languageEnglish
Pages (from-to)1-11
Number of pages11
JournalBiopolymers
Volume85
Issue number1
DOIs
StatePublished - Jan 2007

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Circular Dichroism
Disulfides
Molecular dynamics
Dichroism
Molecular Dynamics Simulation
Circular dichroism spectroscopy
Computer simulation
Amides
Peptides
Amino acids
Vibration
Amino Acids
Spectrum Analysis
Incidence

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Biophysics

Cite this

Optical spectroscopic elucidation of β-turns in disulfide bridged cyclic tetrapeptides. / Borics, Attila; Murphy, Richard F.; Lovas, Sándor.

In: Biopolymers, Vol. 85, No. 1, 01.2007, p. 1-11.

Research output: Contribution to journalArticle

Borics, Attila ; Murphy, Richard F. ; Lovas, Sándor. / Optical spectroscopic elucidation of β-turns in disulfide bridged cyclic tetrapeptides. In: Biopolymers. 2007 ; Vol. 85, No. 1. pp. 1-11.
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