Exoglucanase/cellobiohydrolase (EC 3.2.1.176) hydrolyzes a β-1,4-glycosidic bond from the reducing end of cellulose and releases cellobiose as the major product. Three complex crystal structures of the glycosyl hydrolase 48 (GH48) cellobiohydrolase S (ExgS) from Clostridium cellulovorans with cellobiose, cellotetraose and triethylene glycol molecules were solved. The product cellobiose occupies subsites +1 and +2 in the open active-site cleft of the enzyme-cellotetraose complex structure, indicating an enzymatic hydrolysis function. Moreover, three triethylene glycol molecules and one pentaethylene glycol molecule are located at active-site subsites -2 to -6 in the structure of the ExgS-triethylene glycol complex shown here. Modelling of glucose into subsite -1 in the active site of the ExgS-cellobiose structure revealed that Glu50 acts as a proton donor and Asp222 plays a nucleophilic role.
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http://dx.doi.org/10.1107/S2053230X15015915 | DOI Listing |
J Biotechnol
January 2025
Chair of Microbiology, Technical University of Munich, Freising, Germany.
Cellulose from lignocellulosic biomass (LB) is of increasing interest for the production of commodity chemicals. However, its use as substrate for fermentations is a challenge due to its structural complexity. In this context, the highly cellulolytic Clostridium cellulovorans has been considered an interesting microorganism for the breakdown of LB.
View Article and Find Full Text PDFBeilstein J Org Chem
July 2024
Laboratory of Microbiology, Institute of Chemistry, National Autonomous University of Mexico, Mexico City, 04510, Mexico.
Antimicrobial resistance presents a substantial threat to global public health, demanding urgent attention and action. This study focuses on lanthipeptides, ribosomally encoded peptides that display significant structural diversity and hold promising potential as antibiotics. Genome mining was employed to locate biosynthetic gene clusters (BGCs) containing class II lanthipeptide synthetases encoded by genes.
View Article and Find Full Text PDFSci Rep
November 2023
Molecular Microbial Ecology Group, Institute of Aquatic Ecology, University of Girona, Carrer Maria Aurèlia Capmany 40, 17003, Girona, Spain.
Co-cultures of clostridia with distinct physiological properties have emerged as an alternative to increase the production of butanol and other added-value compounds from biomass. The optimal performance of mixed tandem cultures may depend on the stability and fitness of each species in the consortium, making the development of specific quantification methods to separate their members crucial. In this study, we developed and tested a multiplex qPCR method targeting the 16S rRNA gene for the simultaneous quantification of Clostridium acetobutylicum, Clostridium carboxidivorans and Clostridium cellulovorans in co-cultures.
View Article and Find Full Text PDFMicroorganisms
December 2022
Department of Life Sciences, Graduate School of Bioresources, Mie University, 1577 Kurimamachiya, Tsu 514-8507, Japan.
The cellulolytic system of mainly consisting of a cellulosome that synergistically collaborates with non-complexed enzymes was investigated using cellulosic biomass. The cellulosomes were isolated from the culture supernatants with shredded paper, rice straw and sugarcane bagasse using crystalline cellulose. Enzyme solutions, including the cellulosome fractions, were analyzed by SDS-PAGE and Western blot using an anti-CbpA antibody.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2022
College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Sichuan, Chengdu, 610064, P. R. China.
The degradation of recalcitrant polysaccharides such as cellulose and chitin requires the synergistic functionality of processive glycosidase (GH) cocktails. Understanding the fundamental phenomenon of processivity is of biological and economic importance for the conversion of biomass into biofuel. In this work, cellulase family 9 from (Cel9G), which is a processive endoglucanase, was used to elucidate the processive binding mechanism with respect to polysaccharides, since it exhibits a multimodular crystallographic structure.
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