They reconstruct the evolution of a wonderful family of ancient bacterial proteins

Scientists have managed to reconstruct the evolution of a family of ancient bacterial proteins with potential industrial and biotechnological applications.

The international team that carried out the research, including, among others, Laura Mascotti, from the National Council for Scientific and Technical Research (CONICET) in Argentina, and Guang Yang, from the University of Groningen in the Netherlands, reconstructed the evolution of a family of enzymes with high potential for biotechnological applications: Baeyer-Villiger monooxygenases (BVMOs).

BVMOs are enzymes that take oxygen from the air to transform molecules through an oxidation process. Through a technique called “ancestral sequence reconstruction,” which allows us to know, through the study of its ancestors, how a protein acquires a certain function over time, the scientific team reconstructed its evolutionary history and detected when acquired the ability to use oxygen.

According to Laura Mascotti, CONICET researcher at the Institute of Histology and Embryology of Mendoza (IHEM), these enzymes have existed in microorganisms for millions of years, long before the Earth’s atmosphere was enriched with oxygen. “BVMOs are very ancient proteins and we can trace their evolution with certainty to the first bacterial populations, a little before the ‘great oxygenation event’, approximately between 2.5 million and 2.3 million years ago,” explains the scientist, recently incorporated into IHEM, to establish an Evolutionary Biochemistry group, after several years of work in the Netherlands.

“Our idea was to understand when they acquired the ability to use oxygen and how. To do this, what we did was approach the problem from evolutionary biochemistry, which in simple terms consists of studying the evolution of the family of enzymes to be able to trace over time how a function changed or how it acquired it. For us it is very important to study this because we wanted to understand how monooxygenases ‘learned’ to use oxygen,” adds the scientist.

Laura Mascotti. (Photo: CONICET. CC BY 2.5 AR)

The study showed that BVMOs evolved in a series of steps, starting from a protein that had no activity and subsequently acquiring reactivity and specificity until they transformed into active enzymes. Taken together, the results of the study illustrate how an intrinsically complex catalytic mechanism emerged during evolution.

BVMOs have a high potential for biotechnological applications, such as the production of polymers. However, they have not yet been used on a large scale due to their instability under operating conditions and the need to adjust their selectivity in certain cases. The science aimed at deepening their functioning, and that of enzymes in general, allows for improving their practical application. “Evolutionary biochemistry generates results that are key to later applying rational or semi-rational designs of enzymatic variants with industrial application because it allows us to know and define what the ‘functional determinants’ of an enzyme are. On the other hand, I think it is worth highlighting that the reconstruction of ancestral sequences is not just another genetic engineering tool, but rather an approach to ‘dissect/unravel’ functionalities and that it can generate invaluable knowledge to be later used for applied purposes,” concludes the scientist.

The study is titled “Evolution of the catalytic mechanism at the dawn of the Baeyer-Villiger monooxygenases.” And it has been published in the academic journal Cell Reports. (Source: Leonardo Fernández / CONICET. CC BY 2.5 AR)