Molecular mechanisms of a new oxidative enzyme for cellulose depolymerization

• Grant number: 24/22565-4
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: May 01, 2025
• End date: February 28, 2029
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Principal Investigator: Mariana Abrahão Bueno de Morais
• Grantee: Gustavo Henrique Barreto Gimenis
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil

Abstract

Cellulose is the most abundant renewable polymer in nature and its deconstruction is one of the main challenges in converting biomass into biofuels and high-value products. Due to its crystalline structure, its degradation in nature is a slow process carried out by complex enzymatic systems. Recently, our research group identified a novel enzyme from the hidden metagenome of microbial communities specialized in polysaccharide degradation. This enzyme increased the efficiency of lignocellulose deconstruction by up to 20% when integrated into an industrially competitive enzymatic cocktail. Using a multidisciplinary approach, it was proposed that this enzyme, named Cellulose Oxidative Cleaving Enzyme (CelOCE), operates through an oxidative mechanism similar to that of the well-known Lytic Polysaccharide Monooxygenases (LPMOs). However, it presents key differences in sequence, structure, and mode of action. The mechanisms of oxidative enzymes have been studied using combinations of experimental and theoretical approaches, however, many questions remain unanswered in the field of biocatalysis. For the new enzyme CelOCE, novel features of its activity have been identified, including its compact fold, its homodimeric organization and the arrangement of its active site, indicating a distinct mechanism for oxidative action on cellulose. Therefore, this project aims to elucidate the molecular mechanism of CelOCE through computational methods such as molecular docking, density functional theory, molecular dynamics simulations, and hybrid quantum mechanics and molecular mechanics simulations. Understanding the molecular mechanisms by which novel enzymes oxidize recalcitrant substrates represents a crucial step towards sustainable development, enabling the rational design of enzymes for biomass conversion. (AU)