Characterization and Reshaping of a Large and Hydrophobic Nucleophile Pocket in Lipases/Acyltransferases

• Published in: ChemBioChem
• Main Authors: Jan-Deniau, Anne Hélène, Subileau, Maeva, Dubreucq, Eric
• Other Authors: Ingénierie des Agro-polymères et Technologies Émergentes (UMR IATE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: Acyltransfer; Nucleophile binding site; Aqueous medium; molecular structure; structure function relationship; acyltransférase; structure moléculaire; transesterification; lipase; relation structure fonction; [SDV.IDA]Life Sciences [q-bio]/Food engineering; Antarc*; antarcticus
• Online Access: https://hal.science/hal-01918036; https://doi.org/10.1002/cbic.201800279

Lipases/acyltransferases, such as CpLIP2 from Candida parapsilosis and CduLAc from Candida dubliniensis catalyze preferentially acyltransfer over hydrolysis when a suitable nucleophile is present, even in medium with a high thermodynamic activity of water (aW). They are related to CAL‐A from Moesziomyces antarcticus, which in comparison displays a lower acyltransfer ability. The 3D structures of wild‐types and mutants of CAL‐A, CpLIP2 and CduLAc revealed differences in size and hydrophobicity of a large pocket located under the catalytic triad. The kinetic behavior of site‐directed mutants confirmed the role of this pocket in the competition between methanol and water as the nucleophile acceptor for the deacylation step. The mutations provided a better understanding of key structural determinants for the variable levels of acyltransferase ability observed and supported the existence of a complex network of nucleophile interactions within the enzymes. The shape and size of the possible nucleophile pocket identified also suggested that multiple binding sites could exist, supporting the hypothesis of non‐overlapping leaving and accepting nucleophiles binding sites.