title: N-terminal nonrepetitive domain common to dragline, flagelliform, and cylindriform spider silk proteins.
abstract: Spider silk has been extensively studied for its outstanding mechanical properties. Partial intermediate and C-terminal sequences of different spider silk proteins have been determined, and during the past decade also N-terminal domains have been characterized. However, only some of these N-terminal domains have been reported to contain signal peptides, leaving the mechanism whereby they enter the secretory pathway open to speculation. Here we present the sequence of a 394-residue N-terminal region of the Euprosthenops australis major ampullate spidroin 1 (MaSp1). A close comparison with published sequences from other species revealed the presence of N-terminal signal peptides followed by an approximately 130-residue nonrepetitive domain. From secondary structure predictions, helical wheel analysis, and circular dichroism spectroscopy this domain is concluded to contain five alpha-helices and is a conserved constituent of hitherto analyzed dragline, flagelliform, and cylindriform spider silk proteins.
authors.affiliation: Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Rising
authors.forename: Göran
authors.initials: G
authors.lastname: Hjälm
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Engström
authors.forename: Jan
authors.initials: J
authors.lastname: Johansson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D019476:Insect Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D020449:Repetitive Sequences, Amino Acid; D017386:Sequence Homology, Amino Acid; D047011:Silk / Q000737:chemistry*; D013112:Spiders
chemical_list: D017931:DNA Primers; D019476:Insect Proteins; D047011:Silk