title: Pulcherosine, an oxidatively coupled trimer of tyrosine in plant cell walls: its role in cross-link formation.
abstract: An oxidatively coupled trimer of tyrosine has been isolated from hydrolysates of primary cell walls of a tomato cell culture. UV-absorption, fluorescence and 1H NMR spectra showed that the trimer was pulcherosine, composed of isodityrosine and tyrosine oxidatively coupled via a biphenyl linkage such that the aromatic core is 2,2'-dihydroxy-3-phenoxybiphenyl. Pulcherosine could act as an intermediate in the conversion of isodityrosine to the tetramer, di-isodityrosine. Steric considerations show that the three tyrosine units of pulcherosine could not be near-neighbour residues within a single polypeptide chain. Pulcherosine therefore forms inter-polypeptide cross-links and/or wide intra-polypeptide loops.
authors.affiliation: Edinburgh Cell Wall Group, Institute of Cell and Molecular Biology, Edinburgh, U.K.
authors.forename: J D
authors.initials: JD
authors.lastname: Brady
authors.forename: I H
authors.initials: IH
authors.lastname: Sadler
authors.forename: S C
authors.initials: SC
authors.lastname: Fry
mesh_terms: D000595:Amino Acid Sequence; D002473:Cell Wall / Q000378:metabolism; D003432:Cross-Linking Reagents; D006023:Glycoproteins / Q000737:chemistry* / Q000378:metabolism; D018551:Solanum lycopersicum / Q000378:metabolism*; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D006023:Glycoproteins; D010940:Plant Proteins; C005488:extensin protein, plant; C065089:pulcherosine; D014443:Tyrosine