text: Genomics and Proteomics and Interactomics, Oh, My! Researchers Conclude Metabolite-Protein Interactions are Important to Cellular Processes; Could New Omics Be Added to Clinical Laboratories’ Test Menus?
  This potential new source of diagnostic biomarkers could give clinical labs a new tool to diagnose disease earlier and with greater accuracy
  Clinical laboratories may soon have a new “omics” in their toolkit and vocabulary. In addition to genomics and proteomics, anatomic pathologists could also be using “interactomics” to diagnose disease earlier and with increased accuracy.
  “Here, we present a chemoproteomic workflow for the systematic identification of metabolite-protein interactions directly in their native environments,” the researchers wrote. “Our data reveal functional and structural principles of chemical communication, shed light on the prevalence and mechanisms of enzyme promiscuity, and enable extraction of quantitative parameters of metabolite binding on a proteome-wide scale.”
  Interactomics address interactions between proteins and small molecules, according to an article published in Technology Networks. The terms “interactomics” and “omics” were inspired by research that described, for the first time, the interactions and relationships of all proteins and metabolites (A.K.A, small molecules) in the whole proteome.
  Medical laboratories and anatomic pathologists have long understood the interactions among proteins, or between proteins and DNA or RNA. However, metabolite interactions with packages of proteins are not as well known.
  These new omics could eventually be an important source of diagnostic biomarkers. They may, one day, contribute to lower cost clinical laboratory testing for some diseases, as well.
  Metabolite-Protein Interactions are Key to Cellular Processes
  The ETH researchers were motivated to explore the interplay between small molecules and proteins because they have important responsibilities in the body. These cellular processes include:
  “Metabolite-protein interactions control a variety of cellular processes, thereby playing a major role in maintaining cellular homeostasis. Metabolites comprise the largest fraction of molecules in cells. But our knowledge of the metabolite-protein interaction lags behind our understanding of protein-protein or protein-DNA interactomes,” the researchers wrote in Cell.
  Leveraging Limited Proteolysis and Mass Spectrometry
  The researchers used limited proteolysis (LiP) technology with mass spectrometry to discover metabolite-protein interactions. Results aside, experts pointed out that the LiP technology itself is significant.
  “It is one of the few methods that enables the unbiased and proteome-wide profiling of protein conformational changes resulting from interaction of proteins with compounds,” stated a Biognosys blog post.
  Biognosys, a proteomics company founded in 2008, was originally part of a lab at ETH Zurich.
  The ETH team focused on the E. coli bacterial cell in particular and how its proteins and enzymes interact with metabolites.
  More than 1,000 New Interactions Discovered
  The study progressed as follows, according to Technology Networks’ report:
  - “Cellular fluid, containing proteins, was extracted from bacterial cells;
  - “A metabolite was added to each sample;
  - “The metabolite interacted with proteins;
  - “Proteins were cut into smaller pieces by molecular scissors (A.K.A., CRISPR-Cas9);
  - “Protein structure was altered when it interacted with a metabolite;
  - “A different set of peptides emerged when the “molecular scissors” cut at different sites;
  - “Pieces of samples were measured with a mass spectrometer;
  - “Data were obtained, fed into a computer, and structural differences and changes were reconstructed;
  - “1,650 different protein-metabolite interactions were found;
  - “1,400 of those discovered were new.”
  A Vast, Uncharted Metabolite-protein Interaction Network
  The research is a major step forward in the body of knowledge about interactions between metabolites and proteins and how they affect cellular processes, according to Balázs Papp, PhD, Principal Investigator, Biological Research Center of the Hungarian Academy of Sciences.
  “Strikingly, more than 80% of the reported interactions were novel and about one quarter of the measured proteome interacted with at least one of the 20 tested metabolites. This indicates that the metabolite-protein interaction network is vast and largely uncharted,” Papp stated in an ETH Zurich Faculty of 1000 online article.
  According to Technology Networks, “Picotti has already patented the method. The ETH spin-off Biognosys is the exclusive license holder and is now using the method to test various drugs on behalf of pharmaceutical companies.”
  The pharmaceutical industry is reportedly interested in the approach as a way to ascertain drug interactions with cellular proteins and their effectiveness in patient care.
  The ETH Zurich study is compelling, especially as personalized medicine takes hold and more medical laboratories and anatomic pathology groups add molecular diagnostics to their capabilities.
  —Donna Marie Pocius