Rudsander Ulla J, Sandstrom Corine, Piens Kathleen, Master Emma R, Wilson David B, Brumer Iii Harry, Kenne Lennart, Teeri Tuula T
KTH Biotechnology, Swedish Center for Biomimetic Fiber Engineering, AlbaNova, SE-10691 Stockholm, Sweden.
Biochemistry. 2008 May 6;47(18):5235-41. doi: 10.1021/bi702193e. Epub 2008 Apr 11.
1H NMR spectroscopy has been used to analyze the product profiles arising from the hydrolysis of cellooligosaccharides by family GH9 cellulases. The product profiles obtained with the wild type and several active site mutants of a bacterial processive endoglucanase, TfCel9A, were compared with those obtained by a randomly acting plant endoglucanase, PttCel9A. PttCel9A is an orthologue of the Arabidopsis endocellulase, Korrigan, which is required for efficient cellulose biosynthesis. As expected, poplar PttCel9A was shown to catalyze the degradation of cellooligosaccharides by inversion of the configuration of the anomeric carbon. The product analyses showed that the number of interactions between the glucose units of the substrate and the aromatic residues in the enzyme active sites determines the point of cleavage in both enzymes.
1H核磁共振光谱已被用于分析GH9家族纤维素酶水解纤维寡糖产生的产物谱。将细菌持续性内切葡聚糖酶TfCel9A的野生型和几个活性位点突变体所获得的产物谱，与随机作用的植物内切葡聚糖酶PttCel9A所获得的产物谱进行了比较。PttCel9A是拟南芥内切纤维素酶Korrigan的直系同源物，高效纤维素生物合成需要该酶。正如预期的那样，杨树PttCel9A通过异头碳构型的转化催化纤维寡糖的降解。产物分析表明，底物葡萄糖单元与酶活性位点中芳香族残基之间相互作用的数量决定了两种酶的切割点。
