Multi-scale approach for the study of enzymatic N-acylation reaction of amino acids

• Main Author: Dettori, Léna
• Other Authors: Laboratoire Réactions et Génie des Procédés (LRGP), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL), Université de Lorraine, Isabelle Chevalot, Yann Guiavarc'h
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2017
• Subjects: N-acylation; Enzymatic catalysis; Molecular modelisation; Lipase; Aminoacylase; Enzyme immobilization; Catalyse enzymatique; Modélisation moléculaire; Immobilisation d’enzyme; [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering; [CHIM.ORGA]Chemical Sciences/Organic chemistry; [CHIM.GENI]Chemical Sciences/Chemical engineering; Antarc*
• Online Access: https://tel.archives-ouvertes.fr/tel-01835089; https://tel.archives-ouvertes.fr/tel-01835089/document; https://tel.archives-ouvertes.fr/tel-01835089/file/DDOC_T_2017_0346_DETTORI.pdf

N-acylation of amino acids or peptides results in bioactive and/or functional molecules showing increased bioavailability, hydrophobicity and stability. Acylated amino acids have been broadly described as being a kind of surfactant with great surface chemistry properties, interesting biological activities, weak toxicity and low environmental impact. Acylation of amino acids or peptides is being performed chemically at industrial scale. It creates constraints in term of reaction selectivity, environmental safety and cost of polluted wastewater treatment. Enzymatic catalysis is an alternative to chemical acylation reaction. Several enzyme/solvent pairs have already been described in the literature. Their performance are however somewhat limited. The objective of this thesis work was thus to improve the capacity of acylation processes at different scales. At the molecular scale, a study was performed using Candida antarctica’s (CALB) lipase B. Molecular modeling was used to create a methodology coupling docking simulation and interaction calculus that would allow for a better understanding of CALB regioselectivity during lysine acylation by different fatty acids. Studies were also conducted at the reaction level, especially by searching for new aminoacylase-type of biocatalysts in Streptomyces ambofaciens raw extract. Regioselectivity and performance of these enzyme’s catalytic reactions were compared to those of CALB. Results brought into light a promising potential from S. ambofaciens’ aminoacylases in synthesizing acylated amino acids/peptides. Indeed, on top of their ability to catalyse acylation reaction in aqueous solution, these enzymes have a different regioselectivity compared to CALB’s. Regioselectivity targeting N-terminal groups is a rarely researched phenomenon allowing acylation to be performed without modifying amino acids or peptides lateral chains and hence their functionality. In the last part part of this work, studies at process scale were performed. Aminoacylase were first immobilized on ...