Researchers from the Brazilian Center for Research in Energy and Materials (CNPEM), in collaboration with scientists from the Centre National de la Recherche Scientifique (CNRS) and Université Grenoble-Alpes, the University of Campinas (Unicamp), and the University of Cambridge, have discovered an unprecedented mechanism that controls the activity of an enzyme involved in nutrient processing—specifically carbohydrates—carried out by bacteria from the capybara’s gut microbiota.
Three-dimensional structure of the metamorphic enzyme, elucidated using Sirius. Image: Gustavo Gimenis/CNPEM
The study was published in Nature Communications on January 5, 2026, and was funded by the São Paulo Research Foundation (FAPESP) and the National Council for Scientific and Technological Development (CNPq).
The discovery emerged from the analysis of microorganisms associated with Brazilian biodiversity, a field that remains underexplored and rich in new biological systems. In this context, the researchers identified an enzyme present in bacteria from the capybara’s gut microbiota—the largest rodent in the world and endemic to Latin America—capable of functioning as a true “molecular switch”: it turns off under oxidative stress and resumes activity when conditions stabilize.
In practice, this occurs because the enzyme has a metamorphic capacity—that is, it changes shape. Under oxidative stress, essential parts of its structure become disordered, preventing substrate binding and interrupting the biochemical reaction. When the environment becomes favorable again, the structure reorganizes and activity is fully restored. This process is reversible, which is uncommon for this group of enzymes.
“It is as if the enzyme has an on–off molecular switch embedded in its own structure, responding to the chemical conditions of the environment. This mechanism is mediated by a malleable active site that dynamically regulates its activity,” explains Marcele Martins, CNPEM researcher and lead author of the article.
To understand this behavior, the team combined several cutting-edge experimental techniques that allowed them to observe the enzyme’s structure in both active and inactive states. The experiments showed that this alternation depends on the temporary formation of an internal chemical bond known as a disulfide bond, which acts as a structural key to control the protein’s function.
The study used open-access facilities from all CNPEM National Laboratories, including the Manacá beamline at Sirius, as well as Macromolecular Biophysics infrastructure, the Brazilian Biorenewables National Laboratory (LNBR), ROBOLAB, the Brazilian Biosciences National Laboratory (LNBio), cryomicroscopy and electron microscopy facilities, and the Brazilian Nanotechnology National Laboratory (LNNano).
In addition to expanding understanding of how gut microbiota bacteria regulate nutrient utilization, the discovery opens pathways for biotechnological applications, such as the development of more controllable enzymes for industrial and environmental processes.
“This type of regulatory mechanism helps explain how microorganisms adapt to variable environments and also inspires new strategies for using enzymes in technological processes,” Martins adds.
The full article is available at: https://www.nature.com/articles/s41467-025-67225-2.
About LNBR
The Brazilian Biorenewables National Laboratory (LNBR) works to address scientific challenges that are strategic for Brazil in order to promote energy transition and develop a sustainable bioeconomy. Its interdisciplinary competencies in bioprospecting, synthetic biology, biocatalysis, bioprocesses and sustainability are integrated into the development of technologies founded on renewable sources, domestic production chains and Brazilian biodiversity. Its infrastructure on the cutting edge of multi-omics, synthetic biology, precision fermenting, and scaling-up of bioprocesses is open to the scientific community in order to strengthen the national bioeconomy ecosystem and partnerships with the productive sector. The biotechnology platforms developed by LNBR, which are made available for research and innovation, are intended to boost Brazil’s autonomy and competitiveness in the production of biofuels, chemicals and materials. LNBR is part of the Brazilian Center for Research in Energy and Materials (CNPEM) in Campinas, São Paulo, a private, non-profit organization overseen by the Ministry of Science, Technology and Innovation (MCTI).
About CNPEM
The Brazilian Center for Research in Energy and Materials (CNPEM) is home to a state-of-the-art, multi-user and multidisciplinary scientific environment and works on different fronts within the Brazilian National System for Science, Technology and Innovation. A social organization overseen by the Ministry of Science, Technology and Innovation (MCTI), CNPEM is driven by research that impacts the areas of health, energy, renewable materials, and sustainability. It is responsible for Sirius, the largest assembly of scientific equipment constructed in the country, and is currently constructing Project Orion, a laboratory complex for advanced pathogen research. Highly specialized science and engineering teams, sophisticated infrastructure open to the scientific community, strategic lines of investigation, innovative projects involving the productive sector, and training for researchers and students are the pillars of this institution that is unique in Brazil and able to serve as a bridge between knowledge and innovation. CNPEM’s research and development activities are carried out through its four National Laboratories: Synchrotron Light (LNLS), Biosciences (LNBio), Nanotechnology (LNNano), Biorenewables (LNBR), as well as its Technology Unit (DAT) and the Ilum School of Science — an undergraduate program in Science and Technology supported by the Ministry of Education (MEC).
