Structural Model for the Spider Silk Protein Spidroin-1

Author(s)

Aparecido dos Santos-Pinto, Jose Roberto ^{[1, 2]} ; Arcuri, Helen Andrade ^[2] ; Priewalder, Helga ^[3] ; Salles, Heliana Clara ^[2] ; Palma, Mario Sergio ^[2] ; Lubec, Gert ^[1]

Affiliation

^[1] Med Univ Vienna, Dept Pediat, A-1090 Vienna - Austria

^[2] Sao Paulo State Univ, Ctr Study Social Insects, Inst Biosci Rio Claro, Dept Biol, BR-13500 Rio Claro, SP - Brazil

^[3] Geol Survey Austria, Dept Paleontol, A-1230 Vienna - Austria

• Document type: Journal article
• Source: JOURNAL OF PROTEOME RESEARCH; v. 14, n. 9, p. 3859-3870, SEP 2015.
• Web of Science Citations: 7

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 (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. (AU)

• FAPESP's process: 10/19051-6 - Structural analysis of silk proteins of Nephila clavipes spider web by a proteomic approach.
• Grantee: José Roberto Aparecido dos Santos-Pinto
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/26451-9 - Bioprospecting and Structural Analysis of the Silk Proteins of Arthropods by a Proteomics Approach Using nanoLC-ESI-CID/ETD System
• Grantee: José Roberto Aparecido dos Santos-Pinto
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 11/51684-1 - System biology as experimental strategy for discovery of novel natural products in the fauna of venomous arthropods from São Paulo State
• Grantee: Mario Sergio Palma
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants