Proteins are among the most studied molecules in biology, yet new research from the University of Göttingen shows they can still hold surprising secrets. Researchers have discovered previously undetected chemical bonds within archived protein structures, revealing an unexpected complexity in protein chemistry.

These newly identified nitrogen-oxygen-sulfur (NOS) linkages broaden our understanding of how proteins respond to oxidative stress, a condition where harmful oxygen-based molecules build up and can damage proteins, DNA, and other essential parts of the cell. The new findings are published in Communications Chemistry.

The research team systematically re-analyzed over 86,000 high-resolution protein structures from the Protein Data Bank, a global public repository of protein structures, using a new algorithm that they developed inhouse called SimplifiedBondfinder. This pipeline combines machine learning, quantum mechanical modeling, and structural refinement methods to reveal subtle chemical bonds that were missed by conventional analyses.