- 著者
- Keisuke Kojima Naoki Sunagawa Yoshihisa Yoshimi Theodora Tryfona Masahiro Samejima Paul Dupree Kiyohiko Igarashi
- 出版者
- The Japanese Society of Applied Glycoscience
- 雑誌
- Journal of Applied Glycoscience (ISSN:13447882)
- 巻号頁・発行日
- pp.jag.JAG-2021_0017, (Released:2022-03-05)
- 被引用文献数
- 6
Endo-type xylanases are key enzymes in microbial xylanolytic systems, and xylanases belonging to glycoside hydrolase (GH) families 10 or 11 are the major enzymes degrading xylan in nature. These enzymes have typically been characterized using xylan prepared by alkaline extraction, which removes acetyl sidechains from the substrate, and thus the effect of acetyl groups on xylan degradation remains unclear. Here, we compare the ability of GH10 and 11 xylanases, PcXyn10A and PcXyn11B, from the white-rot basidiomycete Phanerochaete chrysosporium to degrade acetylated and deacetylated xylan from various plants. Product quantification revealed that PcXyn10A effectively degraded both acetylated xylan extracted from Arabidopsis thaliana and the deacetylated xylan obtained by alkaline treatment, generating xylooligosaccharides. In contrast, PcXyn11B showed limited activity towards acetyl xylan, but showed significantly increased activity after deacetylation of the xylan. Polysaccharide analysis using carbohydrate gel electrophoresis showed that PcXyn11B generated a broad range of products from native acetylated xylans extracted from birch wood and rice straw, including large residual xylooligosaccharides, while non-acetylated xylan from Japanese cedar was readily degraded into xylooligosaccharides. These results suggest that the degradability of native xylan by GH11 xylanases is highly dependent on the extent of acetyl group substitution. Analysis of 31 fungal genomes in the Carbohydrate- Active enZymes database indicated that the presence of GH11 xylanases is correlated to that of carbohydrate esterase family 1 acetyl xylan esterases (AXEs), while this is not the case for GH10 xylanases. These findings may imply co-evolution of GH11 xylanases and CE1 AXEs.
- 著者
- Kiyohiko Igarashi Satoshi Kaneko Motomitsu Kitaoka Masahiro Samejima
- 出版者
- The Japanese Society of Applied Glycoscience
- 雑誌
- Journal of Applied Glycoscience (ISSN:13447882)
- 巻号頁・発行日
- vol.67, no.2, pp.51-57, 2020-05-20 (Released:2020-05-20)
- 参考文献数
- 40
- 被引用文献数
- 2
Cellobiose dehydrogenase (CDH) is a flavocytochrome catalyzing oxidation of the reducing end of cellobiose and cellooligosaccharides, and has a key role in the degradation of cellulosic biomass by filamentous fungi. Here, we use a lineup of glucose/xylose-mixed β-1,4-linked disaccharides and trisaccharides, enzymatically synthesized by means of the reverse reaction of cellobiose phosphorylase and cellodextrin phosphorylase, to investigate the substrate recognition of CDH. We found that CDH utilizes β-D-xylopyranosyl-(1→4)-D-glucopyranose (Xyl-Glc) as an electron donor with similar Km and kcat values to cellobiose. β-D-Glucopyranosyl-(1→4)-D-xylopyranose (Glc-Xyl) shows a higher Km value, while xylobiose does not serve as a substrate. Trisaccharides show similar behavior; i.e., trisaccharides with cellobiose and Xyl-Glc units at the reducing end show similar kinetics, while the enzyme was less active towards those with Glc-Xyl, and inactive towards those with xylobiose. We also use docking simulation to evaluate substrate recognition of the disaccharides, and we discuss possible molecular mechanisms of substrate recognition by CDH.
- 著者
- Sosyu Tsutsui Kiyoshi Sakuragi Kiyohiko Igarashi Masahiro Samejima Satoshi Kaneko
- 出版者
- The Japanese Society of Applied Glycoscience
- 雑誌
- Journal of Applied Glycoscience (ISSN:13447882)
- 巻号頁・発行日
- vol.67, no.1, pp.17-22, 2020-02-20 (Released:2020-02-20)
- 参考文献数
- 29
- 被引用文献数
- 4
Sugarcane bagasse is a useful biomass resource. In the present study, we examined the efficacy of ammonia pretreatment for selective release of hemicellulose from bagasse. Pretreatment of bagasse with aqueous ammonia resulted in significant loss of xylan. In contrast, pretreatment of bagasse with anhydrous ammonia resulted in almost no xylan loss. Aqueous ammonia or anhydrous ammonia-pretreated bagasse was then subjected to enzymatic digestion with a xylanase from the glycoside hydrolase (GH) family 10 or a xylanase from the GH family 11. The hydrolysis rate of xylan in bagasse pretreated with aqueous ammonia was approximately 50 %. In contrast, in the anhydrous ammonia-treated bagasse, xylan hydrolysis was > 80 %. These results suggested that anhydrous ammonia pretreatment would be an effective method for preparation of sugarcane bagasse for enzymatic hydrolysis to recover xylooligosaccharides.
- 著者
- Maki Ishiguro Tomonobu Hori Takuya Ishida Makoto Yoshida Koji Takabatake Satoshi Kaneko Kiyohiko Igarashi Masahiro Samejima
- 出版者
- Japanese Society for Plant Biotechnology
- 雑誌
- Plant Biotechnology (ISSN:13424580)
- 巻号頁・発行日
- vol.27, no.3, pp.273-281, 2010-06-25 (Released:2010-07-15)
- 参考文献数
- 26
- 被引用文献数
- 5 4
The basidiomycete Flammulina velutipes is one of the most popular edible mushrooms in Japan, and has the ability to grow on cellulosic biomass as a carbon source. In this study, we have isolated two enzymes belonging to glycoside hydrolase (GH) family 7 (FvCel7A and FvCel7B) from the cellulose-grown culture of the fungus, and cloned cDNAs encoding these enzymes by utilizing a transcriptomic database of this fungus. Although both enzymes contain a catalytic domain belonging to GH family 7, only FvCel7A has the family 1 carbohydrate-binding module at the C-terminal. Sequence comparison indicated that FvCel7A and FvCel7B have a similar pattern of disulfide bonds and similar active site architecture to other fungal GH family 7 enzymes, but show small differences at loop regions covering the active site, which may affect the reactivity of cellulosic substrates.