title: Solution structures of calcitonin-gene-related-peptide analogues of calcitonin-gene-related peptide and amylin.
abstract: Near-u.v. and far-u.v. c.d. spectra of human alpha-calcitonin-gene-related peptide (h alpha CGRP), analogues and fragments of CGRP and amylin were recorded in aqueous solution and in trifluoroethanol (TFE)/water mixtures. All peptides contained significant amounts of alpha-helix in aqueous solution, and this amount increased on adding TFE. The helical content was unaffected by pH and salt. However, amylin contained much less helix than CGRP and the c.d. spectrum was more temperature-sensitive. A band in the near-u.v. c.d. spectrum of CGRP (but not present in the spectrum of amylin) was attributed to the disulphide bond in CGRP. The intensity of this band was pH-dependent and titrated with a pKa of 6.5, suggesting the involvement of histidine ionization.
authors.affiliation: Celltech Ltd., Slough, Berks, U.K.
authors.forename: J A
authors.initials: JA
authors.lastname: Hubbard
authors.forename: S R
authors.initials: SR
authors.lastname: Martin
authors.forename: L C
authors.initials: LC
authors.lastname: Chaplin
authors.forename: C
authors.initials: C
authors.lastname: Bose
authors.forename: S M
authors.initials: SM
authors.lastname: Kelly
authors.forename: N C
authors.initials: NC
authors.lastname: Price
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry*; D015740:Calcitonin Gene-Related Peptide / Q000031:analogs & derivatives / Q000737:chemistry*; D002942:Circular Dichroism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D058228:Islet Amyloid Polypeptide; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D012996:Solutions; D014270:Trifluoroethanol; D014867:Water
chemical_list: D000682:Amyloid; D058228:Islet Amyloid Polypeptide; D010446:Peptide Fragments; D012996:Solutions; D014867:Water; D014270:Trifluoroethanol; D015740:Calcitonin Gene-Related Peptide