Integrated proteomic and functional mass spectrometry workflow for comprehensive ricin characterization at trace...

Area of Science:

• Biochemistry
• Analytical Chemistry
• Toxicology

Background:

• Ricin, a potent plant toxin from Ricinus communis, poses a significant bioterrorism threat.
• Conventional methods struggle to confirm the intact, active holotoxin structure of ricin.
• Distinguishing between ricin chains and the complete holotoxin is crucial for accurate identification.

Purpose of the Study:

• To develop an integrated workflow for sensitive structural and functional detection of ricin.
• To enable the identification of intact ricin at trace levels in complex matrices.
• To provide a method that assesses both chain connectivity and biological activity.

Main Methods:

• An integrated proteomic mass spectrometry workflow combining targeted peptide detection.
• Utilized an inter-chain disulfide-linked peptide as an unambiguous marker for intact ricin.
• Employed optimized immunocapture with magnetic beads for enhanced sensitivity and ricin recovery.

Main Results:

• Achieved high ricin recovery (~80%) and compatibility with nano-LC-MS/MS.
• Demonstrated limits of detection (LOD) down to 10 pg/mL for ricin A- and B-chain peptides.
• Detected the inter-chain linker peptide at 500 pg/mL, confirming intact ricin structure.
• Exhibited good repeatability with average CV values below 20% across different matrices.

Conclusions:

• The developed workflow enables simultaneous assessment of ricin chain connectivity and biological activity.
• Offers increased confidence in ricin identification compared to conventional mass spectrometry approaches.
• Provides unique insights into the functionality of ricin, crucial for bioterrorism preparedness.