PH-Dependent Interaction between C-Peptide and Phospholipid Bicelles. (4th June 2012)

• Record Type: Journal Article
• Authors: Unnerståle, Sofia; Mäler, Lena
• Other Names: Herrmann Andreas Academic Editor.
• Is Part Of: Journal of biophysics. Volume 2012(2012)
• Publication Date: 2012-06-04
• Subjects: Biophysics -- Periodicals; Biophysics; Biophysical Phenomena; Biophysics; Periodical; Periodicals; Electronic journals; Fulltext; Internet Resources; Periodicals; 571.4
• DOI: 10.1155/2012/185907
• Languages: English
• ISSNs: 1687-8000

Abstract

Abstract : C-peptide is the connecting peptide between the A and B chains of insulin in proinsulin. In this paper, we investigate the interaction between C-peptide and phospholipid bicelles, by circular dichroism and nuclear magnetic resonance spectroscopy, and in particular the pH dependence of this interaction. The results demonstrate that C-peptide is largely unstructured independent of pH, but that a weak structural induction towards a short stretch of β -sheet is induced at low pH, corresponding to the isoelectric point of the peptide. Furthermore, it is demonstrated that C-peptide associates with neutral phospholipid bicelles as well as acidic phospholipid bicelles at this low pH. C-peptide does not undergo a large structural rearrangement as a consequence of lipid interaction, which indicates that the folding and binding are uncoupled. In vivo, local variations in environment, including pH, may cause C-peptide to associate with lipids, which may affect the aggregation state of the peptide.