title: Epiphycan from salmon nasal cartilage is a novel type of large leucine-rich proteoglycan.
abstract: Chum salmon (Oncorhynchus keta) nasal cartilage was examined by next-generation DNA sequencing and mass spectrometric analyses, and 14 types of proteoglycans including epiphycan (EPY) were found. A cDNA encoding EPY was cloned and sequenced. The cDNA encoded 589 amino acids comprised a glycosaminoglycan (GAG) domain containing 55 potential GAG-modified sites (Ser-Gly and/or Gly-Ser), a cysteine cluster and 6 leucine-rich repeats. EPY was purified from salmon nasal cartilage and the structure of the GAG was characterized. As a result of unsaturated disaccharide analysis, GAG was found to be composed of chondroitin 6-sulfate (58.0%), chondroitin 4-sulfate (26.5%) and non-sulfated chondroitin (15.3%). The average molecular weight of GAG was estimated to be 3.0 × 10(4). Ser-100 and Ser-103 were identified as serine residues substituted by GAG chains by chemical modification and mass spectrometric analysis. More than 50 serine residues were assumed to be substituted by GAG chains. EPY is heavily substituted by chondroitin sulfate, giving an overall molecular weight of just under 2 × 10(6). EPY from salmon nasal cartilage is a novel type of large leucine-rich proteoglycan.
authors.affiliation: Department of Glycotechnology, Center for Advanced Medical Research, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan. ytatara@cc.hirosaki-u.ac.jp
authors.forename: Yota
authors.initials: Y
authors.lastname: Tatara
authors.forename: Ikuko
authors.initials: I
authors.lastname: Kakizaki
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kuroda
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Suto
authors.forename: Haruna
authors.initials: H
authors.lastname: Ishioka
authors.forename: Masahiko
authors.initials: M
authors.lastname: Endo
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002809:Chondroitin Sulfates / Q000737:chemistry; D003001:Cloning, Molecular; D029941:Fish Proteins / Q000737:chemistry* / Q000235:genetics; D006031:Glycosylation; D008969:Molecular Sequence Data; D055171:Nasal Cartilages / Q000737:chemistry*; D017685:Oncorhynchus keta / Q000235:genetics*; D017434:Protein Structure, Tertiary; D011509:Proteoglycans / Q000737:chemistry* / Q000235:genetics
chemical_list: D029941:Fish Proteins; D011509:Proteoglycans; D002809:Chondroitin Sulfates
keywords: epiphycan; glycosaminoglycan; leucine-rich repeat proteoglycan; proteoglycan; salmon nasal cartilage