Paper accepted: “Enzymatic production of all fourteen partially acetylated chitosan tetramers using different chitin deacetylases acting in forward or reverse mode”

Lea Hembach and her co-authors’ paper on the biotechnological production of a full set of partially acetylated chitosan tetramers has just been accepted for publication in “Scientific Reports”. Over the past years, we have acquired quite some expertise in heterologously expressing and characterising bacterial and fungal chitin deacetylases. We found that they differ in their subsite specificities leading to different products: when acting on fully acetylated chitin oligomers, some of the chitin deacetylases remove the acetyl group only on certain positions - such as at or next to the non-reducing end of the substrate. Other enzymes removed all acetyl groups except for some specific ones, e.g. at the non-reducing and reducing end. Using and combining these chitin deacetylases, we were already able to produce a surprisingly large number of different, fully defined chitosan oligomers. Lea now found that these same enzymes can also be used in reverse, attaching acetyl groups to glucosamine units instead of removing them from N-acetylglucosamine units. And amazingly, the enzymes retain their subsite preferences. This discovery now allowed her to produce all fourteen possible tetramers! These (and other paCOS produced in this way) are already now proving to be a powerful tool to decipher the “language of sugars” - a dream about to come true!