Precision synthesis of reducing-end thiol-modified cellulose enabled by enzyme selection

We provide here the underlying data of the publication "Precision synthesis of reducing-end thiol-modified cellulose enabled by enzyme selection". Please find the abstract below. Enzyme-catalyzed iterative <em>β</em>-1,4-glycosylation of <em>β</em>-glycosides is promising for bottom-up polymerization of reducing-end-modified cello-oligosaccharide chains. Self-assembly of the chains from solution yields crystalline nanocellulose materials with properties that are tunable by the glycoside group used. Cellulose chains with a reducing-end thiol group are of interest to install a controllable pattern of site-selective modifications into the nanocellulose material. Selection of the polymerizing enzyme (cellodextrin phosphorylase; CdP) was pursued here to enhance the synthetic precision of <em>β</em>-1-thio-glucose conversion to generate pure “1-thio-cellulose” (≥95%) unencumbered by plain (unlabeled) cellulose resulting from enzymatic side reactions. The CdP from <em>Clostridium stercorarium</em> (<em>Cs</em>CdP) was 21 times more active on <em>β</em>-1-thio-glucose (0.17 U/mg; 45 °C) than the CdP from <em>Clostridium cellulosi</em> (<em>Cc</em>CdP), and it lacked hydrolase activity, which is substantial in <em>Cc</em>CdP, against the α-D-glucose 1-phosphate donor substrate. The combination of these enzyme properties indicated that <em>Cs</em>CdP is a practical catalyst for 1-thio-cellulose synthesis directly from <em>β</em>-1-thio-glucose (8 h; 25 mol% yield) that does not require a second enzyme (cellobiose phosphorylase), which was essential when using the less selective <em>Cc</em>CdP. The 1-thio-cellulose chains had an average degree of polymerization of ∼10 and were assembled into highly crystalline cellulose II crystallinity material.