Research demonstrated how to invert an enzymatic activity of a photoreceptor protein

Plants and bacteria adapt to their environment with the help of many photoreceptors, like red light-sensing phytochromes. With phytochromes, plants for example can evade shade or bacteria start pigment production.

Phytochromes consist of a photosensory part and a signaling part that is usually a histidine kinase in bacteria. 

An international collaboration between the groups of Academy researcher Heikki Takala from the University of Jyväskylä and Professor Andreas Möglich from the University of Bayreuth have revealed details on histidine kinase signaling. 

In the study, they applied their pREDusk tool, which  enables the control of bacterial protein production with red light. This optogenetic tool is based on the function of a bacterial phytochrome. 

“Optogenetics aims to control cellular events with light, and bacterial phytochromes have traits that makes them especially good for this purpose,” Heikki Takala explains. 

Histidine kinases exhibit two competing enzymatic activities: kinase activity and phosphatase activity. The researchers showed how the delicate balance between these activities is fine-tuned. They also revealed that certain changes in a linker region between photosensory and signaling parts of the protein may even invert this enzymatic balance.

The process led to development of an inverted pREDusk tool that, unlike its predecessor, can activate bacterial protein production with red light. 

“We named this new tool ‘pDERusk’. This name first started as an unintended typo, but we noticed that would be a perfect name for an inverted ‘pREDusk’ tool,” Takala concludes.