SC Investigator’s New Approach to Capturing Multiprotein Complexes Highlighted in Journal of Proteome Research


A LBNL project led by Dr. Mark Biggin has developed an enhanced approach to rapidly separate intact multiprotein complexes from cells. These multiprotein complexes, often called molecular machines, play critical roles in every aspect of the biochemistry of the cell but are often difficult to isolate and study intact. Traditionally, these complexes are captured using biological tags that are genetically and laboriously inserted into different proteins in the complex one at a time. The new approach eliminates the need for these tags. The “tagless” approach involves removing the cell’s soluble content followed by several gentle chromatographic steps that leave the complexes intact. The complexes are separated from one another based on properties such as electric charge and molecular weight. At the end of the process there is a high probability that only one complex is clustered in one or a small number of related fractions. Mass spectrometry is used to confirm the identity of the proteins. The separation approach is being automated, providing researchers with a new tool to rapidly determine how these complexes and their associated biological processes change in a microbe or a plant exposed to different environmental conditions or genetic modifications. This work was highlighted in the Journal of Proteome Research.