8B48

Structure of Lentithecium fluviatile carbohydrate esterase from the CE15 family (LfCE15C)

Summary for 8B48

• Entry DOI: 10.2210/pdb8b48/pdb
• Descriptor: Carbohydrate esterase family 15 protein, alpha-D-mannopyranose-(1-3)-beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (6 entities in total)
• Functional Keywords: lignocellulose degradation, hydrolase
• Biological source: Lentithecium fluviatile
• Total number of polymer chains: 4
• Total formula weight: 176637.55

Authors

Scholzen, K.,Mazurkewich, S.,Poulsen, J.C.N.,Larsbrink, J.,Lo Leggio, L. (deposition date: 2022-09-20, release date: 2023-06-07, Last modification date: 2024-02-07)

Primary citation

Mazurkewich, S.,Scholzen, K.C.,Brusch, R.H.,Poulsen, J.C.N.,Theibich, Y.,Huttner, S.,Olsson, L.,Larsbrink, J.,Lo Leggio, L.
Structural and functional investigation of a fungal member of carbohydrate esterase family 15 with potential specificity for rare xylans.
Acta Crystallogr D Struct Biol, 79:545-555, 2023

PubMed Abstract: In plant cell walls, covalent bonds between polysaccharides and lignin increase recalcitrance to degradation. Ester bonds are known to exist between glucuronic acid moieties on glucuronoxylan and lignin, and these can be cleaved by glucuronoyl esterases (GEs) from carbohydrate esterase family 15 (CE15). GEs are found in both bacteria and fungi, and some microorganisms also encode multiple GEs, although the reason for this is still not fully clear. The fungus Lentithecium fluviatile encodes three CE15 enzymes, of which two have previously been heterologously produced, although neither was active on the tested model substrate. Here, one of these, LfCE15C, has been investigated in detail using a range of model and natural substrates and its structure has been solved using X-ray crystallography. No activity could be verified on any tested substrate, but biophysical assays indicate an ability to bind to complex carbohydrate ligands. The structure further suggests that this enzyme, which possesses an intact catalytic triad, might be able to bind and act on more extensively decorated xylan chains than has been reported for other CE15 members. It is speculated that rare glucuronoxylans decorated at the glucuronic acid moiety may be the true targets of LfCE15C and other CE15 family members with similar sequence characteristics.

PubMed: 37227091
DOI: 10.1107/S205979832300325X

Experimental method

X-RAY DIFFRACTION (2.65 Å)