Crystallization and preliminary X‐ray diffraction analysis of the N‐terminal domain of Paenibacillus barcinonensis xylanase 10C containing the CBM22‐1–CBM22‐2 tandem

A construct containing the CBM22‐1–CBM22‐2 tandem forming the N‐terminal domain of Paenibacillus barcinonensis xylanase 10C (Xyn10C) has been purified and crystallized. A xylan‐binding function and an affinity for mixed β‐1,3/β‐1,4 glucans have previously been demonstrated for some members of the CBM22 family. The sequence of the tandem is homologous to the N‐terminal domains found in several thermophilic enzymes. Crystals of this tandem were grown by the streak‐seeding method after a long optimization strategy. The structure has been determined by molecular replacement to a resolution of 2.43 Å and refinement is under way. This study represents the first structure containing two contiguous CBM22 modules, which will contribute to a better understanding of the role that this multiplicity plays in fine‐tuning substrate affinity.