Frandsen, KEH, Tovborg, M, Jørgensen, CI et al. (15 more authors) (2019) Insights into an unusual Auxiliary Activity 9 family member lacking the histidine brace motif of lytic polysaccharide monooxygenases. The Journal of Biological Chemistry, 294 (45). pp. 17117-17130. ISSN 0021-9258
Abstract
Lytic polysaccharide monooxygenases (LPMOs) are redox-enzymes involved in biomass degradation. All characterized LPMOs possess an active site of two highly conserved histidine residues coordinating a copper ion (the histidine brace), which are essential for LPMO activity. However, some protein sequences that belong to the AA9 LPMO family, display a natural N-terminal His to Arg substitution (Arg-AA9). These are found almost entirely in the phylogenetic fungal class Agaricomycetes, associated with wood-decay, but no function has been demonstrated for any Arg-AA9. Through bioinformatics, transcriptomic and proteomic analyses we present data, which suggest that Arg-AA9 proteins could have a hitherto unidentified role in fungal degradation of lignocellulosic biomass in conjunction with other secreted fungal enzymes. We present the first structure of an Arg-AA9, LsAA9B, a naturally occurring protein from Lentinus similis. The LsAA9B structure reveals gross changes in the region equivalent to the canonical LPMO copper binding site, whilst features implicated in carbohydrate binding in AA9 LPMOs have been maintained. We obtained a structure of LsAA9B with xylotetraose bound on the surface of the protein although with considerably different binding mode compared to other AA9 complex structures. In addition, we have found indications of protein phosphorylation near the N-terminal Arg and the carbohydrate binding site, for which the potential function is currently unknown. Our results are strong evidence that Arg-AA9s function markedly different from canonical AA9 LPMO, but nonetheless may play a role in fungal conversion of lignocellulosic biomass.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | Published under license by The American Society for Biochemistry and Molecular Biology, Inc. This is an author produced version of a paper published in the Journal of Biological Chemistry. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | His-brace, N-terminal Arg AA9, Biomass degradation, Lytic polysaccharide monooxygenase, Phosphorylation, Xylooligosaccharide. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Molecular and Cellular Biology (Leeds) > Structural Molecular Biology (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 16 Sep 2019 13:36 |
Last Modified: | 20 Nov 2019 04:23 |
Status: | Published |
Publisher: | American Society for Biochemistry and Molecular Biology |
Identification Number: | 10.1074/jbc.ra119.009223 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:150731 |