Projects per year
Abstract
Acetylated glucuronoxylan is one of the most common types of hemicellulose in nature. The structure is formed by a β-(1→4)-linked D-xylopyranosyl (Xylp) backbone that can be substituted with an acetyl group at O-2 and O-3 positions, and α-(1→2)-linked 4-O-methylglucopyranosyluronic acid (MeGlcpA). Acetyl xylan esterases (AcXE) that target mono-or doubly acetylated Xylp are well characterized; however, the previously studied AcXE from Flavobacterium johnsoniae (FjoAcXE) was the first to remove the acetyl group from 2-O-MeGlcpA-3-O-acetyl-substituted Xylp units, yet structural characteristics of these enzymes remain unspecified. Here, six homologs of FjoAcXE were produced and three crystal structures of the enzymes were solved. Two of them are complex structures, one with bound MeGlcpA and another with acetate. All homologs were confirmed to release acetate from 2-O-MeGlcpA-3-O-acetyl-substituted xylan, and the crystal structures point to key structural elements that might serve as defining features of this unclassified carbohydrate esterase family. Enzymes comprised two domains: N-terminal CBM domain and a C-terminal SGNH domain. In FjoAcXE and all studied homologs, the sequence motif around the catalytic serine is Gly-Asn-Ser-Ile (GNSI), which differs from other SGNH hydrolases. Binding by the MeGlcpA-Xylp ligand is directed by positively charged and highly conserved residues at the interface of the CBM and SGNH domains of the enzyme.
Original language | English |
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Article number | 2655 |
Number of pages | 15 |
Journal | Molecules |
Volume | 27 |
Issue number | 9 |
Early online date | 20 Apr 2022 |
DOIs | |
Publication status | Published - 1 May 2022 |
MoE publication type | A1 Journal article-refereed |
Keywords
- acetyl xylan esterase
- carbohydrate esterase
- SGNH hydrolase
- xylan
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Dive into the research topics of 'Elucidating Sequence and Structural Determinants of Carbohydrate Esterases for Complete Deacetylation of Substituted Xylans'. Together they form a unique fingerprint.Projects
- 2 Finished
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BIOSEMBL: Transaminases for BIOcatalytic cascades for hemicellulose reasSEMBly
Penttinen, L. (Project Member), Dahiya, D. (Project Member) & Master, E. (Principal investigator)
01/09/2018 → 30/04/2021
Project: Other external funding: Other foreign funding
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BHIVE: Bio-derived HIgh Value polymers through novel Enzyme function
Mollerup, F. (Project Member), Jurak, E. (Project Member), Aumala, V. (Project Member), Karppi, J. (Project Member), Virtanen, S. (Project Member), Littunen, K. (Project Member), Mai-Gisondi, G. (Project Member), Monschein, M. (Project Member), Pohto, A. (Project Member), Dahiya, D. (Project Member), Leamon, A. K. M. A. A. (Project Member) & Master, E. (Principal investigator)
01/09/2015 → 31/12/2020
Project: EU: ERC grants