β-Hairpin stabilization in a 28-residue peptide derived from the β- subunit sequence of human chorionic gonadotropin hormone

R. A.G.D. Silva, Simon A. Sherman, Timothy A. Keiderling

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

The β-subunit of the human chorionic gonadotropin (hCG) hormone, which is believed to be related to certain types of cancer, contains three hairpin- like fragments. To investigate the role of β-hairpin formation in the early stages of the hCGβ folding, a 28-residue peptide with the sequence RDVRFESIRLPGSPRGVNPVVSYAVALS, corresponding to the H3-β hairpin fragment (residues 60-87) of the hCGβ subunit, was studied under various conditions using three optical spectroscopic methods: Fourier transform in spectroscopy, electronic CD, and vibrational CD. Environmental conditions are critical factors for formation of secondary structure in this peptide. TFE : H2O mixed solvents induced helical formation. Formation of β-structure in this peptide, which may be related to the native β-hairpin formation in the intact hormone, was found to be induced only under conditions such as high concentration, high temperature, and the presence of nonmicellar sodium dodecyl sulfate concentrations. These findings support a protein folding mechanism for the hCGβ subunit in which an initial hydrophobic collapse, which increases intermolecular interactions in hCGβ, is needed to induce the H3-β hairpin formation.

Original languageEnglish (US)
Pages (from-to)413-423
Number of pages11
JournalBiopolymers
Volume50
Issue number4
DOIs
StatePublished - Oct 5 1999

Keywords

  • CD
  • Ir spectroscopy
  • Peptide conformation
  • Protein folding
  • β-hairpin

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Biomaterials
  • Organic Chemistry

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