Dissertation: New building blocks for biotechnology from bacterial red light photoreceptors (Tuure)

Photoreceptors are macromolecules that enable organisms to sense light. In biotechnology, they are used to trigger specific responses in cells.

- Light allows precise spatial and temporal control over cellular processes, which is not possible with pharmaceuticals. In medicine, this could enable targeted treatments only in the cells that require the treatment, explains doctoral researcher Iida Tuure from the University of Jyväskylä.

Iida Tuure focused on bacterial red light sensing photoreceptors known as phytochromes. Her work examined how phytochromes function and identified new variants that could be used for light-based control of cells.

- Together with researchers at the University of Gothenburg, we were able to determine the structure of a phytochrome in its active and resting states more comprehensively than ever before. These structures revealed mechanisms underlying phytochrome activity, which are important to understand to develop new applications, says Tuure.

Towards applications in biotechnology, research and medicine

In nature, phytochromes operate as pairs of two identical phytochromes. In her dissertation, Tuure engineered phytochromes that paired only with a specific, non-identical phytochrome partner. These mismatched phytochromes were functional only when combined with their cognate counterpart. When studied in bacterial cells, they produced similar light responses as the identical phytochrome pairs, demonstrating their potential for novel approaches to cellular light control.

- Phytochromes are like modular tools whose function can be altered by swapping components, much like changing drill bits on a power drill. These mismatched phytochromes enable an implementation of entirely new functional parts, Tuure explains.

Tuure’s dissertation also reports, for the first time, a naturally occurring phytochrome that binds directly to DNA and regulates gene expression.

- Typically, phytochromes regulate cellular activity through another component, but in the case of this DNA-binding phytochrome, this middle step is bypassed. A similar blue light receptor that binds DNA has been widely used in various applications, and this newly discovered phytochrome could convert those systems under red light control. Red light is more suitable for medical applications as it penetrates tissues deeper than blue light, notes Tuure.

M.Sc. Iida Tuure defends her doctoral dissertation "Modular shuffling for diverse phytochrome functionalities” on Friday 6th of March at 12.00 at Agora Auditorio 2 (Ag B105). Opponent is Principal Scientist Alex Jones (National Physical Laboratory, UK) and custos is Senior Lecturer Heikki Takala. The language of the event is English.

The thesis "Modular shuffling for diverse phytochrome functionalities” is available in the JYX archive at: 

Further information:

• Doctoral Researcher Iida Tuure, iida.m.tuure@jyu.fi