期刊
PLANT JOURNAL
卷 104, 期 3, 页码 752-767出版社
WILEY
DOI: 10.1111/tpj.14964
关键词
clustered heatmap of expression profiles; evolution; glycoside hydrolase 16 family; homo- and hetero-transglycosylation; mutants; pectin fragment; RT-qPCR
资金
- VEGA (Slovakia) [2/0058/16, 2/0137/20]
- DoktoGrant (Slovakia) [APP0075]
- Villum Foundation [00017489]
- Australian Research Council (Australia) [DP120100900]
- University of Adelaide (Australia)
- Huaiyin Normal University (China)
We report on the homo- and hetero-transglycosylation activities of the HvXET3 and HvXET4 xyloglucan xyloglucosyl transferases (XET; EC 2.4.1.207) from barley (Hordeum vulgareL.), and the visualisation of these activities in young barley roots using Alexa Fluor 488-labelled oligosaccharides. We discover that these isozymes catalyse the transglycosylation reactions with the chemically defined donor and acceptor substrates, specifically with the xyloglucan donor and the penta-galacturonide [alpha(1-4)GalAp](5)acceptor - the homogalacturonan (pectin) fragment. This activity is supported by 3D molecular models of HvXET3 and HvXET4 with the docked XXXG donor and [alpha(1-4)GalAp](5)acceptor substrates at the -4 to +5 subsites in the active sites. Comparative sequence analyses of barley isoforms and seed-localised TmXET6.3 from nasturtium (Tropaeolum majusL.) permitted the engineering of mutants of TmXET6.3 that could catalyse the hetero-transglycosylation reaction with the xyloglucan/[alpha(1-4)GalAp](5)substrate pair, while wild-type TmXET6.3 lacked this activity. Expression data obtained by real-time quantitative polymerase chain reaction ofHvXETtranscripts and a clustered heatmap of expression profiles of the gene family revealed thatHvXET3andHvXET6co-expressed but did not share the monophyletic origin. Conversely,HvXET3andHvXET4shared this relationship, when we examined the evolutionary history of 419 glycoside hydrolase 16 family members, spanning monocots, eudicots and a basal Angiosperm. The discovered hetero-transglycosylation activity in HvXET3 and HvXET4 with the xyloglucan/[alpha(1-4)GalAp](5)substrate pair is discussed against the background of roles of xyloglucan-pectin heteropolymers and how they may participate in spatial patterns of cell wall formation and re-modelling, and affect the structural features of walls.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据