31AO

A. niger ManA in covalent complex with pseudotrisaccharide inhibitor

Summary for 31AO

• Entry DOI: 10.2210/pdb31ao/pdb
• Related: 29QD
• Descriptor: Probable mannan endo-1,4-beta-mannosidase A, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, beta-D-mannopyranose-(1-4)-beta-D-mannopyranose, ... (6 entities in total)
• Functional Keywords: mannosidase, hydrolase
• Biological source: Aspergillus niger
• Total number of polymer chains: 1
• Total formula weight: 39374.40

Authors

Gote, T.A.,Armstrong, Z.,Tedeschi, M.,Lit, V.A.J.,Ram, A.F.J.,Davies, G.J.,Overkleeft, H.S. (deposition date: 2026-05-20, release date: 2026-07-22)

Primary citation

Tedeschi, M.,Lit, V.A.J.,McGregor, N.G.S.,Gote, T.,Kooloth Valappil, P.,Arentshorst, M.,Florea, B.I.,Gagestein, B.,Armstrong, Z.,Codee, J.D.C.,Nin-Hill, A.,Rovira, C.,Ram, A.F.J.,Davies, G.J.,Overkleeft, H.S.
The development of activity-based mannanase probes.
Chem Sci, 2026

PubMed Abstract: β-Mannanases are endo-acting glycoside hydrolases (GHs) that cleave β-1,4 glycosidic linkages in mannan-rich plant cell wall polysaccharides. They find application in the food and paper industries. Activity-based probes (ABPs) are powerful tools for GH profiling in complex biological samples, yet to date, bespoke ABPs reporting on mannanases have not been reported. Here, we describe the synthesis of cyclophellitol-inspired ABPs based on mannobiose, mannotriose, and glucomannose, and their use in reporting mannanase activities in secretomes from saprophytic bacteria and fungi grown on mannan-containing biomass polysaccharides. In addition to mannanases, our ABPs also labelled cellulases in secretomes from both and , which may indicate broader ("negative-subsite") substrate specificity in these enzymes. Mechanistic proof of active-site nucleophile labelling by our ABPs was obtained for both ManA and Man26C by X-ray crystallography and for both ManA and Man26A by mass spectrometry. Together, our results establish mannanase-targeted ABPs that may find use alongside existing reagents that report on retaining GHs that process other bulk polysaccharides.

PubMed: 42445515
DOI: 10.1039/d6sc04720c

Experimental method

X-RAY DIFFRACTION (1.419 Å)