Photo credit: www.sciencedaily.com

Innovative Bioluminescent Proteins Pave the Way for Advanced Biomedical Imaging

Bioluminescence, a fascinating natural phenomenon found in various organisms, such as fireflies and jellyfish, has attracted considerable scientific interest. Researchers are increasingly looking to harness the genetic mechanisms behind this light-emitting process to enhance applications in biomedicine.

At the University of California, Santa Cruz, Assistant Professor Andy Yeh is at the forefront of developing entirely synthetic proteins capable of bioluminescence. His work aims to establish non-invasive techniques for bioimaging, diagnostics, and drug discovery. A recent study published in the esteemed journal Chem details a new class of bioluminescent proteins developed by Yeh and his research team, characterized by their small size, efficiency, and remarkable stability, allowing them to emit different colors of light for real-time imaging in both cellular and animal models.

This innovative approach falls under the realm of de novo protein design, a cutting-edge field that recently garnered the 2024 Nobel Prize in Chemistry for several scientists, including David Baker, who was Yeh’s post-doctoral advisor. The new proteins were created utilizing deep learning software for protein design from Baker’s lab, along with structural prediction methodologies developed by DeepMind, whose founder also received the Nobel accolade.

“We refer to it as de novo protein design because these proteins are computationally generated from the ground up – they aren’t found in nature and don’t follow any evolutionary precedents. We utilized concepts recognized by the Nobel Prize to create new light-emitting enzymes that can function as optical probes for biological investigations,” Yeh explained.

Advancing Imaging Techniques Beyond Fluorescence

Traditionally, researchers and medical professionals have relied on fluorescence imaging to explore diseases, facilitate drug research, and other applications. However, fluorescence imaging necessitates external light for excitation. This illumination can invoke responses from all nearby cells, generating background noise that complicates the identification of specific targets.

In contrast, bioluminescence imaging operates without external excitation. The light generated from bioluminescent reactions is devoid of background interference, significantly improving the capability to image deeper biological features, such as tumors.

The findings from this study indicate that the researchers’ newly engineered light-emitting proteins are functional at molecular, cellular, and whole organism levels, making them versatile tools for various scientific inquiries. They are particularly advantageous for non-invasive in vivo imaging, enabling real-time observation of biological processes occurring deep within tissues, all without the necessity for sample extraction.

Simultaneous Visualization of Multiple Biological Processes

The engineered proteins possess “orthogonal” properties, meaning their reactive centers are specifically tailored to interact uniquely with their intended light-emitting molecules. This specificity enables the new enzymes to coexist harmoniously with existing natural light-emitting enzymes, allowing for combined usage.

“The reaction we designed is highly specific, making it compatible with other light-emitting enzymes that researchers might be employing,” Yeh noted. “While scientists already use naturally occurring light-emitting enzymes for diverse biological studies, our work does not aim to replace these existing tools but rather to expand the toolkit available to the research community with improved options.”

Yeh and his colleagues have also innovated a technique to modify the color emitted by their proteins. Although traditional bioluminescent enzymes typically emit blue light, this new approach enables the emission of green, yellow, orange, and red light through efficient energy transfer mechanisms. This adaptability allows researchers and clinicians to observe various biological phenomena simultaneously, a process known as “multiplexing,” which is critical for investigating intricate processes like cancer progression.

Embracing a New Era in De Novo Protein Design

One of the standout characteristics of these de novo proteins is their high thermostability, which prevents unfolding at elevated temperatures—an advantage that sets them apart from many naturally occurring bioluminescent enzymes. This stability promises easier applications for point-of-care diagnostics, reducing the complications often associated with the need for temperature-controlled shipping.

“We’ve successfully created light-emitting enzymes that possess optimal protein folding that nature does not always align with during evolution,” Yeh asserted. “This work represents a pioneering achievement in demonstrating that artificial light-emitting enzymes can yield sufficient photons in vertebrate models for bioimaging. As computational design methods continue to improve, so too will the quality of the enzymes we produce. As David Baker rightly stated, we are merely at the onset of the de novo protein design era.”

Source
www.sciencedaily.com