Comparative study of human and salmon calcitonin secondary structure in solutions with low dielectric constants.
Molecular conformations of salmon (sCT) and human ( hCT) calcitonin in media with different concentrations of methanol/water and trifluoroethanol/water have been investigated by fluorescence, circular dichroism (CD) and infrared spectroscopy techniques. In these media, sCT and hCT adopt an alpha-helical structure comprising up to 40-48% of the amino acids. CD experiments reveal that for both peptides, the ordering of the Cys1-Cys7 disulfide link and the alpha-helix formation can be distinguished. Disulfide bond ordering is similar in both calcitonins. sCT adopts the alpha-helical structure more readily than hCT, as solvent polarity is reduced. In 2,2,2-trifluoroethanol (TFE)/water mixtures the alpha-helix formation for both hCT and sCT is a two-step process. The first alpha-helix formation step occurs at lower TFE concentrations (less than 11 mol% TFE for hCT and 6 mol% TFE for sCT). The second alpha-helix formation step represents 50 and 23% of the whole conformational change for hCT and sCT, respectively. Tyrosine fluorescence measurements correlate with the far ultraviolet CD changes associated with the peptide backbone. hCT is seen to adopt a left-handed, extended conformation in aqueous media below -50 degrees C.[1]References
- Comparative study of human and salmon calcitonin secondary structure in solutions with low dielectric constants. Arvinte, T., Drake, A.F. J. Biol. Chem. (1993) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg
