title: Long-range periodic sequence of the cement/silk protein of Stenopsyche marmorata: purification and biochemical characterisation.
abstract: The long-range periodic amino acid sequence of the bifunctional silk/cement protein from larvae of the caddisfly, Stenopsyche marmorata, is discussed in this study. The protein, named the S. marmorata silk protein (Smsp-1), was first purified to electrophoretic homogeneity. The results of Edman-based sequencing of Smsp-1 tryptic digests were consistent with the amino acid sequence deduced from a cDNA clone of the Smsp-1 gene. All undetected amino acids in the Edman-based sequencing were encoded as Ser, suggesting the presence of O-phospho-Ser. (31)P-NMR and an O-phospho-amino acid analysis successfully showed that the O-phospho-Ser residue occurred in a clustered manner, serving a cement function for Smsp-1. Two patterns of non-phosphorylated repeats, -SLGPYGDPRGDXLGPYGG- (X = V, G or D) and -GVGPYGDGLGPYGG-, were enriched in Smsp-1 compared with the O-phospho-Ser cluster, and have fibre-forming functions.
authors.affiliation: Institute of High Polymer Research, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano Prefecture, Japan. kohkawa@shinshu-u.ac.jp
authors.forename: Kousaku
authors.initials: K
authors.lastname: Ohkawa
authors.forename: Yumi
authors.initials: Y
authors.lastname: Miura
authors.forename: Takaomi
authors.initials: T
authors.lastname: Nomura
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Arai
authors.forename: Koji
authors.initials: K
authors.lastname: Abe
authors.forename: Masuhiro
authors.initials: M
authors.lastname: Tsukada
authors.forename: Kimio
authors.initials: K
authors.lastname: Hirabayashi
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D001483:Base Sequence; D015723:Gene Library; D007313:Insecta / Q000033:anatomy & histology / Q000737:chemistry* / Q000235:genetics; D007814:Larva / Q000033:anatomy & histology / Q000737:chemistry / Q000235:genetics; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010766:Phosphorylation; D020539:Sequence Analysis, Protein; D047011:Silk / Q000737:chemistry* / Q000302:isolation & purification*; D013045:Species Specificity
chemical_list: D000596:Amino Acids; D047011:Silk