X-ray diffraction data of PbAcE

PbAcE also has a shorter loop and different residue composition in the β4–α3 and β5–α4 regions near the substrate binding site. Flexible subunit movements and different active site loop conformations may enable the strong low-temperature activity and broad substrate specificity of PbAcE. In addition, PbAcE was found to have strong activity against antibiotic compound substrates, such as cefotaxime and 7-amino cephalosporanic acid (7-ACA).

In conclusion, the PbAcE structure and our biochemical results provide the first example of a cold-active acetyl xylan esterase and a starting template for structure-based protein engineering. This manuscript describes the thorough characterization of a new member of the C7 family of carbohydrate esters, specifically the acetyl xylan esterase (AXE) from Paenibacillus sp (PbAcE). This is the first characterization of a cold-active AXE and the enzyme has a number of potential industrial applications.