Elucidation of effect of phase separation on conformation and dynamics of spider silk proteins

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15738
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 43020:Structural biochemistry-related
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Oktaviani Nur Alia 国立研究開発法人理化学研究所, 環境資源科学研究センター, 基礎科学特別研究員 (70753838)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: NMR / spider silk / protein / structure / mechanism / LLPS

Outline of Final Research Achievements

In this fiscal year, I investigated the effect of phase separation on conformation and dynamics of the repetitive domain and full length minispidroin NR6C and NR12C. The tyrosine residue of the repetitive domain was found to be affected upon LLPS phenomenon. Then, we made a mutant on the repetitive domain which substituted the tyrosine with serine residue. The mutant does not have an effect on the conformattion and dynamics of minispidroin. However, we found a drastic effect on the mutant, where the oligomerization was suppressed at higher kPi concentration, suggesting the important role of tyrosine residues in promoting oligomerization upon LLPS phenomenon. Overall, we found that C-terminal domain (CTD) and tyrosine from the repetitive domain are important as stickers which mediate the oligomerization on the LLPS formation.

Free Research Field

protein NMR

Academic Significance and Societal Importance of the Research Achievements

In natural spinning process, spidroins undergo the liquid-liquid phase separation (LLPS). Since LLPS is one of the emerging topics in biology, thus this study is useful not only to understand the mechanism of natural spinning process, but also to obtain the insight into the molecular basis of LLPS.