title: Protein secondary structure of Green Lynx spider dragline silk investigated by solid-state NMR and X-ray diffraction.
abstract: In this study, the secondary structure of the major ampullate silk from Peucetia viridans (Green Lynx) spiders is characterized by X-ray diffraction and solid-state NMR spectroscopy. From X-ray diffraction measurement, β-sheet nanocrystallites were observed and found to be highly oriented along the fiber axis, with an orientational order, fc≈0.98. The size of the nanocrystallites was determined to be on average 2.5nm×3.3nm×3.8nm. Besides a prominent nanocrystalline region, a partially oriented amorphous region was also observed with an fa≈0.89. Two-dimensional (13)C-(13)C through-space and through-bond solid-state NMR experiments were employed to elucidate structure details of P. viridans silk proteins. It reveals that β-sheet nanocrystallites constitutes 40.0±1.2% of the protein and are dominated by alanine-rich repetitive motifs. Furthermore, based upon the NMR data, 18±1% of alanine, 60±2% glycine and 54±2% serine are incorporated into helical conformations.
authors.affiliation: Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ 85287-1604, United States.
authors.forename: Dian
authors.initials: D
authors.lastname: Xu
authors.affiliation: Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ 85287-1604, United States.
authors.forename: Xiangyan
authors.initials: X
authors.lastname: Shi
authors.affiliation: Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ 85287-1604, United States.
authors.forename: Forrest
authors.initials: F
authors.lastname: Thompson
authors.affiliation: Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ 85287-1604, United States.
authors.forename: Warner S
authors.initials: WS
authors.lastname: Weber
authors.affiliation: Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ 85287-1604, United States.
authors.forename: Qiushi
authors.initials: Q
authors.lastname: Mou
authors.affiliation: Department of Chemistry and Biochemistry, Magnetic Resonance Research Center, Arizona State University, Tempe, AZ 85287-1604, United States. Electronic address: jyarger@gmail.com.
authors.forename: Jeffery L
authors.initials: JL
authors.lastname: Yarger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D019476:Insect Proteins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D047011:Silk / Q000737:chemistry* / Q000648:ultrastructure; D013112:Spiders / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D019476:Insect Proteins; D047011:Silk
keywords: Green Lynx; Peucetia viridans; Solid-state NMR; Spider silk; Wide-angle X-ray diffraction