Structural Model for the Spider Silk Protein Spidroin-1.
J Proteome Res
; 14(9): 3859-70, 2015 Sep 04.
Article
em En
| MEDLINE
| ID: mdl-26211688
ABSTRACT
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 (11) and submitted to molecular dynamics simulation. The resulting models presented high content of coils, a higher percentage of α-helix, and an almost neglected content of 310-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.
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Base de dados:
MEDLINE
Assunto principal:
Aranhas
/
Modelos Moleculares
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Seda
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Fibroínas
Limite:
Animals
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article