木聚糖酶特征序列与最适pH定量关系

研究G/11家族木聚糖酶特征序列与其最适pH的定量构效关系,建立逐步回归方程,模型的相关系数为0.975,显著水平p<0.000 1.利用该方程,计算各木聚糖酶的pH值,结果表明,仅有2个木聚糖酶的最适合pH计算值与实测值相差大于0.6,而有6个木聚糖酶最适pH计算值与测定值相差小于0.1,平均绝对百分比误差为5.91%,平均绝对误差为0.26个pH单位,所得结果优于用二肽进行逐步回归所得模型的结果.通过对计算结果和已知晶体结构的木聚糖酶的比较发现,在1YNA中,这6个氨基酸分别是Pro,Leu,Val,Val,Val和Tyr,前3个氨基酸残基位于第7个转角处,更适合作为突变的位点.

Quantitative Relationship of Characteristic Sequence and Optimum pH in G/11 Family Xylanases

The quantitative structure-activity relationship(QSAR) of xylanase in G/11 family was studied based on the the stepwise regression,the correlation coefficient of the model was 0.975 and model reached a significant level(p< 0.000 1).The optimal pH of xylanases was calculated based on the model and the results was shown as below: there were only two xylanses with the deviation between the calculated pHs the optimum pHs larger than 0.6,while there 6 xylanases with the deviation less than 0.1 the mean absolute percent error was 5.91%,the mean absolute error were 0.26 pH unit,respectively.It was superior when compared with the reported stepwise regression model based on dipeptide composition.Meanwhile,by comparing the calculating results with the crystal structure of xylanse,in 1YNA,the six amino acids were Pro,Leu,Val,Aal and Tyr,the first three amino acids were located in the seventh turn,which meant that they were suit for mutation.