A rice GT61 glycosyltransferase possesses dual activities mediating 2-O-xylosyl and 2-O-arabinosyl substitutions of xylan

Main conclusion A member of the rice GT61 clade B is capable of transferring both 2-O-xylosyl and 2-O-arabinosyl residues onto xylan and another member specifically catalyses addition of 2-O-xylosyl residue onto xylan. Abstract Grass xylan is substituted predominantly with 3-O-arabinofuranose (Araf) as well as with some minor side chains, such as 2-O-Araf and 2-O-(methyl)glucuronic acid [(Me)GlcA]. 3-O-Arabinosylation of grass xylan has been shown to be catalysed by grass-expanded clade A members of the glycosyltransferase family 61. However, glycosyltransferases mediating 2-O-arabinosylation of grass xylan remain elusive. Here, we performed biochemical studies of two rice GT61 clade B members and found that one of them was capable of transferring both xylosyl (Xyl) and Araf residues from UDP-Xyl and UDP-Araf, respectively, onto xylooligomer acceptors, whereas the other specifically catalysed Xyl transfer onto xylooligomers, indicating that the former is a xylan xylosyl/arabinosyl transferase (named OsXXAT1 herein) and the latter is a xylan xylosyltransferase (named OsXYXT2). Structural analysis of the OsXXAT1- and OsXYXT2-catalysed reaction products revealed that the Xyl and Araf residues were transferred onto O-2 positions of xylooligomers. Furthermore, we demonstrated that OsXXAT1 and OsXYXT2 were able to substitute acetylated xylooligomers, but only OsXXAT1 could xylosylate GlcA-substituted xylooligomers. OsXXAT1 and OsXYXT2 were predicted to adopt a GT-B fold structure and molecular docking revealed candidate amino acid residues at the predicted active site involved in binding of the nucleotide sugar donor and the xylohexaose acceptor substrates. Together, our results establish that OsXXAT1 is a xylan 2-O-xylosyl/2-O-arabinosyl transferase and OsXYXT2 is a xylan 2-O-xylosyltransferase, which expands our knowledge of roles of the GT61 family in grass xylan synthesis. Graphical Abstract.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:259

Enthalten in:

Planta - 259(2024), 5 vom: 08. Apr.

Sprache:

Englisch

Beteiligte Personen:

Zhong, Ruiqin [VerfasserIn]
Zhou, Dayong [VerfasserIn]
Phillips, Dennis R. [VerfasserIn]
Adams, Earle R. [VerfasserIn]
Chen, Lirong [VerfasserIn]
Rose, John P. [VerfasserIn]
Wang, Bi-Cheng [VerfasserIn]
Ye, Zheng-Hua [VerfasserIn]

Links:

Volltext [lizenzpflichtig]

BKL:

42.38

Themen:

Arabinosyltransferase
Cell wall
GT61
Grass
Rice
Xylan
Xylosyltransferase

Anmerkungen:

© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

doi:

10.1007/s00425-024-04396-0

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

SPR055451799