全基因组挖掘与分析类芽孢杆菌SSG-1的甘露聚糖水解酶

Genome-wide mining and analysis of mannan hydrolases of Paenibacillus sp. SSG-1

甘露聚糖(mannan)是半纤维素中含量仅次于木聚糖的难水解多糖,发掘将甘露聚糖水解为甘露寡糖的甘露聚糖降解酶,对实现其在生物能源、制药、食品、饲料、制浆造纸和纺织等领域的应用,具有极其重要的意义.类芽孢杆菌是甘露聚糖水解酶的新酶源,但鲜见产甘露聚糖酶的报道.利用从土壤中分离获得的产琼胶酶类芽孢杆菌SSG-1的全基因组数据,采用生物信息技术,从全基因组角度挖掘其甘露聚糖水解酶.共挖掘获得6条甘露聚糖水解酶,经Pfam、CDD和分子进化分析,WP_089548806.1为GH26家族的内切β-1,4-甘露聚糖酶,WP_089549173.1和WP_089548729.1为GH76家族的α-1,6-甘露聚糖酶,WP_089547966.1、WP_089548481.1和WP_009225474.1为GH2家族的β-甘露糖苷酶.其中,WP_089548806.1和WP_089548729.1为分泌蛋白,多序列比对和结构分析表明WP_089548806.1具有内切β-1,4-甘露聚糖酶保守的底物结合和活性位点,具有β-甘露聚糖酶典型的(β/α)8-TIM桶状结构.本研究成功从类芽孢杆菌SSG-1中挖掘出6个新型甘露聚糖水解酶,可为挖掘新型甘露聚糖水解酶资源以及揭示类芽孢杆菌SSG-1甘露聚糖酶的表达调控机制奠定重要基础.

Mannan, which is the second most abundant hemicellulosic polysaccharide after xylan, is difficult to hydrolyze. The discovery of mannan-degrading enzymes that hydrolyze mannan into mannose oligosaccharides is extremely important for various applications in the fields of bioenergy, pharmaceuticals, food, feed, pulp and paper, and textiles. Paenibacillus, a potential source of mannan-degrading enzymes, is rarely reported to produce mannanases. As such, in this study, whole genome data analysis of agarase-producing Paenibacillus sp. SSG-1 isolated from soil was conducted, and bioinformatics technology was employed to mine the whole genome for mannan hydrolase. We discovered six mannan-degrading enzymes via genome mining. More specifically, Pfam, CDD, and molecular evolution analyses showed that the enzyme WP_089548806.1 was mannan endo-1,4-beta-mannosidase belonging to the GH26 family, while the enzymes WP_089549173.1 and WP_089548729.1 were α-1,6-D-mannanases belonging to the GH76 family, and enzymes WP_089547966.1,WP_089548481.1, and WP_009225474.1 were β-mannanases belonging to the GH2 family. Among these six enzymes, WP_089548806.1 and WP_089548729.1 were secreted proteins. Multiple sequence alignment and structural analysis showed that enzyme WP_089548806.1 had the conserved substrate binding and active site of mannan endo-1,4-beta-mannosidase, and exhibited the typical mannanase structure of a(β/α)8 TIM-barrel fold. Ultimately, in this study, six new mannan hydrolases were successfully extracted from Paenibacillus sp.SSG-1. This work serves as a starting point for the discovery of novel mannan-degrading enzymes and for future work to explore the potential regulatory mechanism of mannanase expression in Paenibacillus sp. SSG-1.