一种新型黄原胶酶CtCel8A-CBM84的构建及性质表征

Construction and characterization of a novel xanthanase Ct Cel8A-CBM84

对来自拟杆菌Paenibacillussp.62047的黄原胶内切酶PspXan9的碳水化合物结合模块PspCBM84进行了密码子优化、全基因合成并与高效的纤维素内切酶CtCel8A进行了融合表达。该基因大小为423bp,编码141个氨基酸残基,与纤维素内切酶CtCel8A融合表达后,编码蛋白理论分子质量为66.7ku,该酶能在大肠杆菌中可溶性表达。酶学性质分析结果表明,碳水化合物结合模块PspCBM84显著提高了纤维素内切酶CtCel8A对黄原胶的切割效率,融合酶的活力提高了1.6倍。融合酶的最适作用温度为60℃,最适pH为5.5,与原纤维素内切酶相比,融合酶的温度稳定性有所提高。融合酶CtCel8A-CBM84能有效切割黄原胶,将其水解为低分子质量产物。

The carbohydrate binding module Psp CBM84 of endoxanthanase Psp Xan9 from Paenibacillus sp.62047 was codon optimized and whole gene synthesized,and fused with efficient endocellulase Ct Cel8A.The size of the gene is 423 bp and encodes 141 amino acid residues.After fusion expression with Ct Cel8A,the theoretical molecular weight of the encoded protein was 66.7 ku.The enzyme could be expressed in E.coli BL21(DE3)solubly.The results of enzymatic property analysis showed that the Psp CBM84 significantly improved the cutting efficiency of endocellulase Ct Cel8A for xanthan.The activity of Ct Cel8A-CBM84 was increased by 1.6 times.The optimum temperature of Ct Cel8A-CBM84 was 60℃and the optimum pH was 5.5.Compared with Ct Cel8A,the temperature stability of Ct Cel8A-CBM84 was improved.The fusion enzyme Ct Cel8A-CBM84 can effectively hydrolyze xanthan into low molecular weight products.