Exploring the unmapped cysteine redox proteoform landscape.

Area of Science:

• Biochemistry
• Proteomics
• Molecular Biology

Background:

• Cysteine residues in proteins can exist in multiple redox states, forming diverse cysteine redox proteoforms.
• The theoretical number of proteoforms increases exponentially with the number of cysteine residues, creating a vast and complex landscape.
• Despite their biological importance, the full extent of cysteine redox proteoforms and their regulatory roles are poorly understood.

Purpose of the Study:

• To advance the theory of cysteine redox proteoforms.
• To scrutinize existing methodological challenges in their detection.
• To propose innovative technologies and a community-wide project for systematic exploration.

Main Methods:

• Review and synthesis of current knowledge on cysteine redox proteoforms.
• Discussion of limitations in existing analytical techniques.
• Elaboration of chemistry-enabled hybrid approaches, combining top-down mass spectrometry (TD-MS) and bottom-up mass spectrometry (BU-MS).

Main Results:

• The theoretical cysteine redox proteoform landscape is vast and largely uncharted.
• Existing methods face significant challenges in comprehensively detecting unique residue-defined proteoforms.
• Hybrid TD-MS and BU-MS approaches offer a technological pathway to map this complex redox terrain.

Conclusions:

• Exploring the cysteine redox proteoform landscape is crucial for understanding redox biology.
• Innovative technologies and collaborative efforts like the proposed Human Cysteine Redox Proteoform Project are needed.
• Mapping cysteine redox proteoforms could reveal novel regulatory mechanisms, biomarkers, and therapeutic targets.