Prevotella copri is a bacterium that can be found in the human gastrointestinal tract. The role of P. copri in the GIT is unclear, and elevated numbers of the microbe have been reported both in dietary fiber-induced improvement in glucose metabolism but also in conjunction with certain inflammatory conditions. These findings raised our interest in investigating the possibility of P. copri to grow on xylan, and identify the enzyme systems playing a role in digestion of xylan-based dietary fibers. Two xylan degrading polysaccharide utilizing loci (PUL10 and 15) were found in the genome, with three and eight glycoside hydrolase (GH) -encoding genes, respectively. Three of them were successfully produced in Escherichia coli: One extracellular enzyme from GH43 (subfamily 12, in PUL10, 60 kDa) and two enzymes from PUL15, one extracellular GH10 (41 kDa), and one intracellular GH43 (subfamily 137 kDa). Based on our results we propose that in PUL15, GH10 (1) is an extracellular endo-1,4-β-xylanase, that hydrolyses mainly glucuronosylated xylan polymers to xylooligosaccharides (XOS); while, GH43_1 in the same PUL, is an intracellular β-xylosidase, catalysing complete hydrolysis of the XOS to xylose. In PUL10, the characterized GH43_12 is an arabinofuranosidase, with a role in degradation of arabinoxylan, catalysing removal of arabinose-residues on xylan.

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利用普氏菌 DSM18205 位点的多糖新型木聚糖降解酶

普氏菌是一种存在于人类胃肠道中的细菌。普氏菌在胃肠道中的作用尚不清楚，据报道，该微生物数量的增加不仅与膳食纤维诱导的葡萄糖代谢改善有关，而且与某些炎症状况有关。这些发现引起了我们对研究普氏菌在木聚糖上生长的可能性的兴趣，并确定在消化基于木聚糖的膳食纤维中发挥作用的酶系统。在基因组中发现了两个木聚糖降解多糖利用位点（PUL10和15），分别具有三个和八个糖苷水解酶（GH）编码基因。其中三种在大肠杆菌中成功生产：一种来自 GH43 的胞外酶（亚科 12，PUL10，60 kDa）和两种来自 PUL15 的酶，一种胞外 GH10（41 kDa）和一种胞内 GH43（亚科 137 kDa）。根据我们的结果，我们提出，在 PUL15 中，GH10 (1) 是一种胞外内切 1,4-β-木聚糖酶，主要将葡萄糖醛酸化木聚糖聚合物水解为低聚木糖 (XOS)；而同一PUL中的GH43_1是一种细胞内β-木糖苷酶，催化XOS完全水解为木糖。在 PUL10 中，特征性的 GH43_12 是一种阿拉伯呋喃糖苷酶，具有降解阿拉伯木聚糖的作用，催化去除木聚糖上的阿拉伯糖残基。