Characterization of a novel multidomain CE15-GH8 enzyme encoded by a polysaccharide utilization locus in the human gut bacterium Bacteroides eggerthii
Journal article, 2021

Bacteroidetes are efficient degraders of complex carbohydrates, much thanks to their use of polysaccharide utilization loci (PULs). An integral part of PULs are highly specialized carbohydrate-active enzymes, sometimes composed of multiple linked domains with discrete functions—multicatalytic enzymes. We present the biochemical characterization of a multicatalytic enzyme from a large PUL encoded by the gut bacterium Bacteroides eggerthii. The enzyme, BeCE15A-Rex8A, has a rare and novel architecture, with an N-terminal carbohydrate esterase family 15 (CE15) domain and a C-terminal glycoside hydrolase family 8 (GH8) domain. The CE15 domain was identified as a glucuronoyl esterase (GE), though with relatively poor activity on GE model substrates, attributed to key amino acid substitutions in the active site compared to previously studied GEs. The GH8 domain was shown to be a reducing-end xylose-releasing exo-oligoxylanase (Rex), based on having activity on xylooligosaccharides but not on longer xylan chains. The full-length BeCE15A-Rex8A enzyme and the Rex domain were capable of boosting the activity of a commercially available GH11 xylanase on corn cob biomass. Our research adds to the understanding of multicatalytic enzyme architectures and showcases the potential of discovering novel and atypical carbohydrate-active enzymes from mining PULs.

Author

Cathleen Kmezik

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Daniel Krska

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Scott Mazurkewich

Wallenberg Wood Science Center (WWSC)

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Johan Larsbrink

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Wallenberg Wood Science Center (WWSC)

Scientific Reports

2045-2322 (ISSN)

Vol. 11 1 17662

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Swedish Research Council (VR) (2016-03931), 2017-01-01 -- 2020-12-31.

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Novo Nordisk Foundation (NNF17OC0027648), 2018-01-01 -- 2020-12-31.

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Driving Forces

Sustainable development

Subject Categories

Industrial Biotechnology

Biochemistry and Molecular Biology

Renewable Bioenergy Research

Cell and Molecular Biology

Biocatalysis and Enzyme Technology

Areas of Advance

Energy

Health Engineering

Life Science Engineering (2010-2018)

Roots

Basic sciences

DOI

10.1038/s41598-021-96659-z

More information

Latest update

9/21/2021