Structure of model peptides based on Nephila clavipes dragline silk spidroin (MaSp1) studied by 13C cross polarization/magic angle spinning NMR.

摘要: To obtain detailed structural information for spider dragline spidroin (MaSp1), we prepared three versions of the consensus peptide GGLGGQGAGAAAAAAGGAGQGGYGGLGSQGAGR labeled with 13C at six different sites. The CP/MAS NMR spectra were observed after treating peptides reagents known to alter silk protein conformations. conformation-dependent chemical shifts and peak deconvolution used determine local structure fractional compositions conformations, respectively. After trifluoroacetic acid (solvent)/diethyl ether (coagulant) treatment, N-terminal region poly-Ala (PLA) sequence, Ala8 Ala10, adopted predominantly α-helix a substantial amount β-sheet. central region, Ala15, Ala18, Leu26, C-terminal Ala31, dominated by either 31-helix or α-helix. There was no indication β-sheet, although broadening indicates that torsion angle distribution is relatively large. 9 M LiBr/d...