Rhomboid proteases are a promising target for new drugs. Now researchers from the Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) have discovered a mechanism for regulating enzyme activity. The key role is played by the dynamics of the gate discovered a few years ago, which opens for a moment when other proteins are broken.
The gates are located in the cell membrane and break other proteins, triggering a signaling cascade in the cell: as an enzyme, rhomboid proteases are involved in many biological processes in the human body, and play a key role in many diseases such as Parkinson’s disease, malaria and cancer. Because of this, they are considered a good target for new drugs. Because of their localization, however, these intramembrane proteins are difficult to study.
In 2019, the research group of Professor Adam Lange from the Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) in Berlin succeeded in creating dynamic images of rhomboid protease for the first time-using solid-state NMR spectroscopy. In their work, the researchers were able to confirm the hypothesis that, in order to break other proteins, a gate opens for a while, which enables the substrates to move from the otherwise anhydrous cell membrane to the hydrous active site of the enzyme. As a result, the substrates of the now cleaved proteins can detach from the cell membrane and trigger many different biological processes in the cell.
Demonstration of correlation between gate dynamics and enzyme activity
In their current study within the UniSysCat Cluster of Excellence, FMP researchers have now demonstrated the importance of the gate for rhomboid protease function. The findings were recently published in Advances in Science. According to the study, there is a clear correlation between gate dynamics and enzyme activity.
Their current work uses not only solid-state NMR spectroscopy, but also other biophysical methods and biochemical functional assays, as well as molecular dynamics simulations. “This time, to understand how the rhomboid protease works, we combined a whole range of experimental and theoretical approaches and methods,” said project leader Adam Lange. “It’s a highlight of this job.”
The researchers used a biophysical model for their experiments. Rhomboid proteases from E. coli bacteria (GlpG)—identical molecules also found in human mitochondria—were biochemically modified to produce different mutants. These mutants have a movable or, on the contrary, a closed gate. If the mutations make it easier to open the gate, the activity of the enzyme increases; when the gate is closed, the activity is stopped, causing the substrate to come against “closed doors,” which means it can no longer be processed.
Molecular dynamics simulations performed by Professor Han Sun’s research group support and extend the experimental results. “For example, we were able to simulate on the computer how wide the gate would have to be opened to allow the substrates to pass through,” Han Sun explained.
FMP doctoral student Claudia Bohg, lead author of the current work, is also involved in the search for new compounds, which are happening in parallel with FMP. “Rhomboid proteases are an important clinical target,” he said. “The new findings will undoubtedly help us make significant progress in this area, too.”
Claudia Bohg et al, Lateral gate opening dynamics regulate rhomboid protease activity, Advances in Science (2023). DOI: 10.1126/sciadv.adh3858
Provided by the Forschungsverbund Berlin eV (FVB)
Citation: How rhomboid protease activity is regulated (2023, July 21) retrieved on 21 July 2023 from https://phys.org/news/2023-07-rhomboid-protease.html
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