title: A glycosylated byssal precursor protein from the green mussel Perna viridis with modified dopa side-chains.
abstract: Foot tissue of the green mussel Perna viridis contains a variety of byssal precursor proteins with the unusual redox-active amino acid, Dopa (-beta-3,4-dihydroxyphenyl-alpha-alanine). Eight proteins were detectable in acidic extracts of the Perna foot by a redox cycling assay with nitroblue tetrazolium. In one of these, however, P. viridis foot protein-1 (Pvfp-1), activity was not due to Dopa, but to another redox-active derivative. Based on specific colorimetric derivatization with Arnow's reagent, ninhydrin and phenylisothiocyanate (Edman), mass spectrometry, the redox-active derivative in Pvfp-1 is not consistent with any known modification. Another uncommon modification of Pvfp-1 involves O-glycosylation of threonine by mannose, glucose or fucose. As in previously characterized fp-1s, the primary sequence of the Pvfp-1 (apparent mass 89 kDa) has two consensus decapeptide motifs; one is APPKPX1TAX2K and the other is APPPAX1TAX2K, where P is Pro/Hyp, and X1 and X2 are difucosylated threonine and a redox sensitive derivative of tyrosine or Dopa, respectively. Of these two unusual residues, X2 is unique to Pvfp-1, whereas O-glycosylated Thr has been previously detected in freshwater mussel fp-1. The sequence homology of Pvfp-1 with the common structural motifs of the fp-1 protein family strongly suggests that the Pvfp-1 functions as the byssal coating (lacquer) protein.
authors.affiliation: Institute of High Polymer Research, Faculty of Textile Science and Technology Shinshu University Tokida 3-15-1 Ueda 386-8567 Japan. kohkawa@giptc.shinshu-u.ac.jp
authors.forename: Kousaku
authors.initials: K
authors.lastname: Ohkawa
authors.forename: Ayako
authors.initials: A
authors.lastname: Nishida
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamamoto
authors.forename: J Herbert
authors.initials: JH
authors.lastname: Waite
mesh_terms: D000268:Adhesiveness; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D049872:Bivalvia / Q000737:chemistry* / Q000502:physiology; D004295:Dihydroxyphenylalanine / Q000737:chemistry; D006031:Glycosylation; D015394:Molecular Structure; D008970:Molecular Weight; D010084:Oxidation-Reduction; D011498:Protein Precursors / Q000737:chemistry* / Q000302:isolation & purification / Q000502:physiology; D014357:Trypsin
chemical_list: D000596:Amino Acids; D011498:Protein Precursors; D004295:Dihydroxyphenylalanine; D014357:Trypsin