title: Conformational preferences of the sequential fragments of the hinge region of the human IgA1 immunoglobulin molecule.
abstract: The mean solution conformation of tetrapeptide fragments spanning the hinge region of human IgA1 was investigated by CD and 13C-NMR methods. Distinct conformational differences for the partial sequences of IgA1 were found. In a series of tetrapeptides having the Thr-Pro-Pro-Thr sequence, the Pro-Pro fragment was ordered to the structure of a type II polyproline helix, but with unordered forms prevailing in the equilibria. In the case of the Pro-Pro-Thr-Pro sequence, a distinct preference for the beta-turn conformation was found. Acetylation of this tetrapeptide shifts the equilibrium towards unordered forms containing some elements of the type II polyproline helix. The peptide Thr-Pro-Ser-Pro exists predominantly in the beta-turn conformation whereas Pro-Ser-Pro-Ser-NH2 has, for the most part an unordered conformation.
authors.affiliation: Institute of Chemistry, Wrocław University, Poland.
authors.forename: I Z
authors.initials: IZ
authors.lastname: Siemion
authors.forename: A
authors.initials: A
authors.lastname: Pedyczak
authors.forename: J
authors.initials: J
authors.lastname: Burton
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D006801:Humans; D007074:Immunoglobulin G; D009682:Magnetic Resonance Spectroscopy; D009842:Oligopeptides; D011487:Protein Conformation
chemical_list: D007074:Immunoglobulin G; D009842:Oligopeptides