Lopes, J.L.S. and Miles, Andrew J. and Whitmore, Lee and Wallace, Bonnie A. (2014) Distinct circular dichroism spectroscopic signatures of polyproline II and unordered secondary structures: applications in secondary structure analyses. Protein Science 23 (12), pp. 1765-1772. ISSN 0961-8368.
Abstract
Circular dichroism (CD) spectroscopy is a valuable method for defining canonical secondary structure contents of proteins based on empirically-defined spectroscopic signatures derived from proteins with known three-dimensional structures. Many proteins identified as being “Intrinsically Disordered Proteins” have a significant amount of their structure that is neither sheet, helix, nor turn; this type of structure is often classified by CD as “other”, “random coil”, “unordered” or “disordered”. However the “other” category can also include polyprolineII (PPII)-type structures, whose spectral properties have not been well-distinguished from those of unordered structures. In this study, synchrotron radiation circular dichroism spectroscopy was used to investigate the spectral properties of collagen and polyproline, which both contain PPII-type structures. Their native spectra were compared as representatives of PPII structures. In addition, their spectra before and after treatment with various conditions to produce unfolded or denatured structures were also compared, with the aim of defining the differences between CD spectra of PPII and disordered structures. We conclude that the spectral features of collagen are more appropriate than those of polyproline for use as the representative spectrum for PPII structures present in typical amino acid-containing proteins, and that the single most characteristic spectroscopic feature distinguishing a PPII structure from a disordered structure is the presence of a positive peak around 220 nm in the former but not in the latter. These spectra are now available for inclusion in new reference data sets used for CD analyses of the secondary structures of soluble proteins.
Metadata
| Item Type: | Article |
|---|---|
| Keyword(s) / Subject(s): | polyproline, collagen, synchrotron radiation circular dichroism spectroscopy, thermal unfolding, intrinsically disordered proteins, secondary structure |
| School: | Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences |
| Research Centres and Institutes: | Bioinformatics, Bloomsbury Centre for (Closed), Structural Molecular Biology, Institute of (ISMB) |
| Depositing User: | Administrator |
| Date Deposited: | 30 Sep 2014 13:28 |
| Last Modified: | 02 Aug 2023 17:12 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/10636 |
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