Paper accepted: “In silico and in vitro analysis of an Aspergillus niger chitin deacetylase to decipher its subsite sugar preferences”

Today, Martin Bonin’s paper on the biochemical and bioinformatic characterisation of a chitin deacetylase from the fungus Aspergillus niger was accepted for publication in the renowned “Journal of Biological Chemistry”. This enzyme was initially studied in our group by Lisanne Hameleers in her Master thesis and then also used by Lea Hembach in her doctoral project. Dr. Thomas Roret and Dr. Gurvan Michel from the CNRS in Roscoff, France, solved the crystal structure, and Dr. Stefan Cord-Landwehr supported the mass spectrometric analyses of the enzyme’s products. We have been interested since many years in using chitin deacetylases to control the pattern of acetylation of chitosans, initially focusing on finding processively acting enzymes. While we did not find compelling evidence for processivity in chitin deacetylases, we increasingly realised that like chitinases and chitosanases, chitin deacetylases possess a series of subsites in their substrate binding site, each accommodating one monomeric unit of the substrate, and that the preferences of these subsites to bind one of the two constituent monomers, GlcN or GlcNAc, determines the pattern of acetylation they produce in their products. Martin’s paper is a thorough investigation of this hypothesis, using both biochemical and bioinformatics approaches. And it is guiding our current engineering of chitin deacetylases, thus contributing significantly to our development of third generation chitosans with defined patterns of acetylation.