Three highly acidic Equisetum XTHs differ from hetero-trans-β-glucanase in donor substrate specificity and are predominantly xyloglucan homo-transglucosylases.
Cell elongation
Equisetum
Hetero-trans-β-glucanase
Heterologous expression
Pichia pastoris
Plant cell wall
Xyloglucan endotransglucosylase
Journal
Journal of plant physiology
ISSN: 1618-1328
Titre abrégé: J Plant Physiol
Pays: Germany
ID NLM: 9882059
Informations de publication
Date de publication:
Aug 2020
Aug 2020
Historique:
received:
13
08
2019
revised:
20
05
2020
accepted:
24
05
2020
pubmed:
17
6
2020
medline:
15
12
2020
entrez:
17
6
2020
Statut:
ppublish
Résumé
Transglycanases are enzymes that remodel the primary cell wall in plants, potentially loosening and/or strengthening it. Xyloglucan endotransglucosylase (XET; EC 2.4.1.207), ubiquitous in land plants, is a homo-transglucanase activity (donor, xyloglucan; acceptor, xyloglucan) exhibited by XTH (xyloglucan endotransglucosylase/hydrolase) proteins. By contrast, hetero-trans-β-glucanase (HTG) is the only known enzyme that is preferentially a hetero-transglucanase. Its two main hetero-transglucanase activities are MLG : xyloglucan endotransglucosylase (MXE) and cellulose : xyloglucan endotransglucosylase (CXE). HTG is highly acidic and found only in the evolutionarily isolated genus of fern-allies, Equisetum. We now report genes for three new highly acidic HTG-related XTHs in E. fluviatile (EfXTH-A, EfXTH-H and EfXTH-I). We expressed them heterologously in Pichia and tested the encoded proteins' enzymic activities to determine whether their acidity and/or their Equisetum-specific sequences might confer high hetero-transglucanase activity. Untransformed Pichia was found to secrete MLG-degrading enzyme(s), which had to be removed for reliable MXE assays. All three acidic EfXTHs exhibited very predominantly XET activity, although low but measurable hetero-transglucanase activities (MXE and CXE) were also detected in EfXTH-H and EfXTH-I. We conclude that the extremely high hetero-transglucanase activities of Equisetum HTG are not emulated by similarly acidic Equisetum XTHs that share up to 55.5% sequence identity with HTG.
Identifiants
pubmed: 32544741
pii: S0176-1617(20)30100-0
doi: 10.1016/j.jplph.2020.153210
pii:
doi:
Substances chimiques
Plant Proteins
0
Glycosyltransferases
EC 2.4.-
xyloglucan - xyloglucosyltransferase
EC 2.4.1.207
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
153210Informations de copyright
Copyright © 2020 Elsevier GmbH. All rights reserved.
Déclaration de conflit d'intérêts
Declaration of Competing Interest A patent application (WO2015044209) has been filed by BASF Agricultural Solutions Belgium NV and The University of Edinburgh for the use of hetero-transglycosylase. F.M., A.H., S.C.F., T.S. and C.H. are inventors.