Characterization of two novel highly active glycoside hydrolase family 53 endo-1,4-β-galactanases and their synergism with other carbohydrases in plant polysaccharide decomposition
Characterization of two novel highly active glycoside hydrolase family 53 endo-1,4-β-galactanases and their synergism with other carbohydrases in plant polysaccharide decomposition
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DOI：
10.1016/j.ijbiomac.2022.10.154
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发表时间：
2022-12-17
影响因子：
8.2
通讯作者：
Wang，Kui
中科院分区：
文献类型：
--
作者：
Zhang，Yurou;Liu，Yun;Wang，Kui
鉴定了两种新的芽孢杆菌糖苷水解酶家族53（GH53）内切-1，4-β-半乳聚糖酶（Bs 936和Bs 4828）。重组Bs 936和Bs 4828分别在pH 5.5/55 °C和pH 6.5/65 °C下显示最大活性。稳定性分析表明，该酶在pH 4.5-10之间是稳定的，在25 °C下孵育12小时后保留超过80%的活性。此外，Bs 936在45 °C下处理2小时后仍保持约75%的活性，而Bs 4828在50 °C下孵育4小时后仍保持完全活性。重要的是，Bs 936和Bs 4828对β-1，4-半乳聚糖表现出良好的活性，对马铃薯半乳聚糖的比活性分别为1859.46和3110.79 U/mg。Bs 4828和Bs 936的Km分别为6.60 mg/mL和707.12 mL/mg/s。广泛的协同作用分析表明，每种内切-1，4-β-半乳聚糖酶分别与其他β-半乳糖苷酶（Bs 937或Bs 4829）、内切-1，5-α-L-阿拉伯糖苷酶（BsAbn 2）和内切葡聚糖酶/内切葡聚糖酶+纤维素酶混合物（BaXynA + LsCel）协同作用，以水解半乳聚糖、去支阿拉伯聚糖/阿拉伯聚糖和预处理的玉米秸秆。Bs 486的相应协同程度分别为1.28、1.17/1.09和1.15，Bs 4828的相应协同程度分别为1.55、1.04/1.08和1.11。这项研究扩展了GH53酶的谱，并证明了两种高活性内切-1，4-β-半乳聚糖酶在多糖水解中的作用。
Two novel Bacillus glycoside hydrolase family 53 (GH53) endo-1,4-β-galactanases (Bs936 and Bs4828) were identified. The recombinant Bs936 and Bs4828 displayed maximal activities at pH 5.5/55 °C and pH 6.5/65 °C, respectively. Stability analyses revealed that the enzymes were stable between pH 4.5–10, retaining over 80% activities after 12 h incubation at 25 °C. Moreover, Bs936 maintained about 75% activity after being treated at 45 °C for 2 h, while Bs4828 kept full activity after 4 h of incubation at 50 °C. Importantly, Bs936 and Bs4828 exhibited good activity towards β-1,4-galactan, showing specific activities of 1859.46- and 3110.79 U/mg towards potato galactan, respectively. The correspondingKmandkcat/Kmwere 4.93 mg/mL and 296.35 mL/mg/s for Bs936, and 6.60 mg/mL and 707.12 mL/mg/s for Bs4828. Extensive synergy assays revealed that each endo-1,4-β-galactanase acted synergistically with the other β-galactosidase (Bs937 or Bs4829), endo-1,5-α-L-arabinosidase (BsAbn2) and an endoxylanase/endoglucanase+cellulase mixture (BaXynA + LsCel) towards the hydrolysis of galactan, debranched arabinan/arabinan, and pretreated corn stover, respectively. The corresponding degrees of synergy were 1.28, 1.17/1.09, and 1.15 for Bs486 and 1.55, 1.04/1.08, and 1.11 for Bs4828, respectively. This study expands the repertoire of GH53 enzymes, and demonstrates the role of two highly active endo-1,4-β-galactanases in polysaccharides hydrolysis.