Structural Model for the Spider Silk Protein Spidroin-1
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Data
2015-09-01
Autores
Aparecido dos Santos-Pinto, Jose Roberto [UNESP]
Arcuri, Helen Andrade [UNESP]
Priewalder, Helga
Salles, Heliana Clara [UNESP]
Palma, Mario Sergio [UNESP]
Lubec, Gert
Título da Revista
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Título de Volume
Editor
Amer Chemical Soc
Resumo
Most reports about the 3-D structure of spidroin-1 have been proposed for the protein in solid state or for individual domains of these proteins. A gel-based mass spectrometry strategy using collision-induced dissociation (CID) and electron-transfer dissociation (ETD) fragmentation methods was used to completely sequence spidroins-1A and -1B and to assign a series of post-translational modifications (PTMs) on to the spidroin sequences. A total of 15 and 16 phosphorylation sites were detected on spidroin-1A and -1B, respectively. In this work, we present the nearly complete amino acid sequence of spidroin-1A and -1B, including the nonrepetitive N- and C-terminal domains and a highly repetitive central core. We also described a fatty acid layer surrounding the protein fibers and PTMs in the sequences of spidroin-1A and -1B, including phosphorylation. Thus, molecular models for phosphorylated spidroins were proposed in the presence of a mixture fatty acids/water (1:1) and submitted to molecular dynamics simulation. The resulting models presented high content of coils, a higher percentage of alpha-helix, and an almost neglected content of 3(10)-helix than the previous models. Knowledge of the complete structure of spidroins-1A and -1B would help to explain the mechanical features of silk fibers. The results of the current investigation provide a foundation for biophysical studies of the mechanoelastic properties of web-silk proteins.
Descrição
Palavras-chave
silk proteins, Nephila clavipes, mass spectrometry, post-translational modification, molecular dynamics
Como citar
Journal Of Proteome Research. Washington: Amer Chemical Soc, v. 14, n. 9, p. 3859-3870, 2015.