Structure-aided function assignment to the transcriptomic conopeptide Am931.

Area of Science:

• Marine biology
• Biochemistry
• Structural biology

Background:

• Next-generation sequencing provides extensive marine cone snail venom peptide data.
• Computational platforms are advancing 3D polypeptide structure prediction from primary sequences.

Purpose of the Study:

• To integrate transcriptomic and computational structural data for structure-aided function assignment of Conus peptides.
• To demonstrate this approach using the C. amadis transcriptomic peptide Am931.

Main Methods:

• Gene sequencing of venom duct transcriptome.
• 3D structure computation using Density Functional Theory (DFT).
• Structure validation using 2D NMR spectroscopy.
• Functional assay of synthetic Am931 on conotoxin folding.

Main Results:

• The 3D structure of Am931 was computed and validated.
• Am931's structure aligns with thioredoxin active sites, featuring a catalytic disulfide conformation.
• Am931 selectively modulates the N-terminal Cys3 thiol, indicating potential disulfide isomerase activity.
• Synthetic Am931 demonstrated catalytic activity in the oxidative folding of α-conotoxin ImI, improving native fold yield.

Conclusions:

• Am931 may function as a disulfide isomerase, modulating conotoxin oxidative folding.
• Integrating new technologies accelerates the discovery of functional conotoxins.
• This structure-function approach advances understanding of marine venom peptides.