Multiple dynamic feature alterations explain the reduced activity of enzymes in organic solvents

VELEZ RUEDA ANA JULIA; MONZON ALEXANDER; IGLESIAS LUIS; PARISI GUSTAVO

Buenos Aires

Conferencia; Fourth International Society for Computational Biology Latin America Bioinformatics Conference (ISCB-LA) 2016; 2016

International Society For Computational Biology

Biocatalysis in anhydrous organic solvents is a common practice still under development but with a large potential in Biotechnology. Basically the use of organic solvents in enzyme catalysis has several advantages over the use of aqueous mediums. Thus, solubility enhancement of compounds that are insoluble in water promotes the use of common organic reagents, reduction in the occurrence of unwanted side reactions and easier removal due to the lower boiling point of these solvents compared to water. The use of organic solvents for enzyme catalyzed reactions sounds awkward, due to the hydrophilic nature of the great majority of enzymes. However, several works have found that proteins crystallized in organic solvents preserve protein fold integrity. Although this structural conservation, it is well stablished that catalytic activity of proteins in organic solvents is lower than in water. In order to explain this diminished activity, we performed a large-scale analysis of proteins crystallized in aqueous and non-aqueous solvents. We found that proteins crystallized in organic solvents show lower conformational diversity when compared with their structures in water, and also, shorter tunnels, lower cavity flexibility, lower number of disordered regions and lower active-site residues mobility. Our results indicate that the increased rigidity of the protein backbone but also the alteration of structures involved in the internalization and migration of substrates from protein surface to active sites located in inner cavities could explain all together the low activity of enzymes in organic solvents. Our results help with the understanding of protein promiscuity and biocatalysis in organic media. Hence, they will have a major impact on the biotechnology.