Researchers at the University of Basel have discovered that the protein "Trigger factor" recognizes a partner by unstable, flexible domains, to then together form a stable protein duo. The work was published last week in Nature Communications.
Misfolded proteins can cause huge problems for a cell. Luckily, there are proteins called chaperones that help with folding and carry out quality control. Trigger factor (TF) is a chaperone protein that is found in Escherichia coli. In this study, Sebastian Hiller's research group has shown that TFs recognize and stabilize each other and when only bound to other proteins can they be stable.
TFs are typically bound near the exit of the ribosome and acts as a "carriage" for the newly created protein from the ribosome. TF will help the new protein fold correctly while on route to the protein's destination.
"In unpaired TF proteins the region that would bind to the ribosome is folded unfavorably and therefore energetically unstable," explains Hiller. "In the search for an energetically favorable, stable structure, this labile domain is continuously reoriented. TFs are able to detect such dynamic regions of a protein, also among each other. Upon recognition, they do not form just one type of protein structure but rather a dynamic ensemble of different spatial arrangements."
The findings can contribute to the understanding of diseases associated with misfolded proteins such as cancer or Alzheimer's disease.
Image: Like an acrobatic duo—single proteins lend each other greater stability. Image courtesy of the University of Basel, Biozentrum.