Light-sensitive enzymes enable bacterial signaling by changing shapes, study reveals

Researchers at the University of Bayreuth and Forschungszentrum Jülich have uncovered that light-sensitive enzymes, known as sensor histidine kinases (SHKs), can switch between two distinct shapes, facilitating signal transmission in bacteria. This groundbreaking study, published on July 2, 2026, in Science Advances, enhances our understanding of bacterial communication and paves the way for advanced biotechnological applications.

Understanding Bacterial Signaling Mechanisms

SHKs play a critical role in bacterial signaling pathways, acting as sensors that respond to environmental stimuli like light. They consist of a detection element and a regulatory component that modulates gene expression in response to these stimuli. Depending on the light conditions, SHKs can either transfer or remove phosphate groups to a regulator, thus influencing various cellular processes.

While the importance of SHKs in bacterial signaling has been established, the exact mechanisms behind their signal transmission have remained largely elusive. The research team from the University of Bayreuth and Forschungszentrum Jülich has now shed light on these processes, revealing how the structural dynamics of SHKs contribute to their signaling functions.

Structural Insights from the New Study

Ulrich Krauss, a member of the Biochemistry I research group at the University of Bayreuth, stated, "In our study, we examined newly engineered light-sensitive SHKs, which can be used as optogenetic tools, both structurally and functionally." This investigation combined crystallographic data with functional analyses to identify the active dark state and the light-induced structural changes in SHKs.

The researchers found that in the absence of light, SHKs adopt an asymmetrical bent form that is active in kinase function. In contrast, exposure to light prompts a transition to a symmetrical, straight structure, which favors phosphatase activity, thereby inhibiting kinase function. This critical shift exemplifies how the enzyme's spatial arrangement dictates its biochemical activity.

Implications for Biotechnology and Biomedicine

The findings from this study have significant implications for the development of optogenetic tools, which allow precise control over biological processes using light. This technology could revolutionize applications in fields such as biomedicine and biotechnology, enabling more targeted and effective treatments.

The research team is now exploring whether this mechanism is universal among other SHKs and how protein dynamics influence signal transduction in light-sensitive proteins. The potential for developing new tools to manipulate cellular functions with light could lead to breakthroughs in various scientific domains.

Key Takeaways from the Research

• The study revealed how light-sensitive SHKs switch between two shapes.
• Asymmetrical form promotes kinase activity; symmetrical form favors phosphatase activity.
• Research could lead to improved optogenetic tools for biomedicine and biotechnology.
• Findings published in Science Advances on July 2, 2026.

This research highlights a pivotal advancement in understanding bacterial signaling mechanisms, offering new avenues for scientific inquiry and technological innovation.