Structure-function analyses reveal that a glucuronoyl esterase from Teredinibacter turnerae interacts with carbohydrates and aromatic compounds
Journal article, 2019

Glucuronoyl esterases (GEs) catalyze the cleavage of ester linkages found between lignin and glucuronic acid moieties on glucuronoxylan in plant biomass. As such, GEs represent promising biochemical tools in industrial processing of these recalcitrant resources. However, details on how GEs interact with their natural substrates are sparse, calling for thorough structurefunction studies. Presented here is the structure and biochemical characterization of a GE, TtCE15A, from the bacterium Teredinibacter turnerae, a symbiont of wood-boring shipworms. To gain deeper insight into enzyme-substrate interactions, inhibition studies were performed with both the WT TtCE15A and variants in which we, by using site-directed mutagenesis, substituted residues suggested to have key roles in binding to or interacting with the aromatic and carbohydrate structures of its uronic acid ester substrates. Our results support the hypothesis that two aromatic residues (Phe-174 and Trp- 376), conserved in bacterial GEs, interact with aromatic and carbohydrate structures of these substrates in the enzyme active site, respectively. The solved crystal structure of TtCE15A revealed features previously not observed in either fungal or bacterial GEs, with a large inserted N-terminal region neighboring the active site and a differently positioned residue of the catalytic triad. The findings highlight key interactions between GEs and complex lignin-carbohydrate ester substrates and advance our understanding of the substrate specificities of these enzymes in biomass conversion.

Author

Jenny Arnling Bååth

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Scott Mazurkewich

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

J. C. N. Poulsen

University of Copenhagen

Lisbeth Olsson

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Leila Lo Leggio

University of Copenhagen

Johan Larsbrink

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Journal of Biological Chemistry

0021-9258 (ISSN) 1083-351X (eISSN)

Vol. 294 16 6635-6644

Structure-function studies of enzymes cleaving covalent bonds between lignin and hemicelluloses

Interreg Öresund-Kattegat-Skagerrak, 2016-12-01 -- 2017-05-31.

Novo Nordisk Fonden, 2018-01-01 -- 2020-12-31.

Interreg Öresund-Kattegat-Skagerrak, 2017-10-01 -- 2018-03-31.

Subject Categories

Biochemistry and Molecular Biology

Structural Biology

Biocatalysis and Enzyme Technology

DOI

10.1074/jbc.RA119.007831

PubMed

30814248

More information

Latest update

5/24/2019