Rapid detection of ribosome inactivating protein toxins by mass-spectrometry-based functional assays

A family of structurally related protein toxins extracted from bacteria or plants have a similar mechanism of action, namely, blocking protein synthesis by ribosome inactivation. Members of this family of ribosome-inactivating proteins (RIP), classified simultaneously as chemical and biological threat agents, include ricin, abrin, and shiga toxins. We have adapted and streamlined mass spectrometry based functional assays, described by others, to develop a rapid, robust, broad-band and fieldable protocol with the primary goal of RIP toxin detection in unknown powder materials. Complementary to intact protein detection and proteomics methods, this protocol involves monitoring the depurination of selected DNA substrates by mass spectrometry. It is being implemented on the CB-TOF system for rapid detection of bio-threats by MALDI MS. Here we illustrate its performance on the example of a plant (ricin) and a bacterial (shiga) RIP toxin.

Figure optionsDownload high-quality image (120 K)Download as PowerPoint slideHighlights
► We have developed a rapid functional assay for robust and broad-band detection of protein toxins in powders.
► The assay is based on monitoring by MALDI mass spectrometry the depurination of two DNA substrates.
► The assay is complementary to methods for intact protein toxin detection including proteomics.