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Article Dans Une Revue Biomacromolecules Année : 2020

Polysaccharide Structures in the Outer Mucilage of Arabidopsis Seeds Visualized by AFM

Résumé

Evidence is presented that the polysaccharide rhamnogalacturonan I (RGI) can be biosynthesized in remarkably organized branched configurations and surprisingly long versions and can self-assemble into a plethora of structures. AFM imaging has been applied to study the outer mucilage obtained from wild-type (WT) and mutant (bxl1-3 and cesa5-1) Arabidopsis thaliana seeds. For WT mucilage, ordered, multichain structures of the polysaccharide RGI were observed, with a helical twist visible in favorable circumstances. Molecular dynamics (MD) simulations demonstrated the stability of several possible multichain complexes and the possibility of twisted fibril formation. For bxl1-3 seeds, the imaged polymers clearly showed the presence of side chains. These were surprisingly regular and well organized with an average length of similar to 100 nm and a spacing of similar to 50 nm. The heights of the side chains imaged were suggestive of single polysaccharide chains, while the backbone was on average 4 times this height and showed regular height variations along its length consistent with models of multichain fibrils examined in MD. Finally, in mucilage extracts from cesa5-1 seeds, a minor population of chains in excess of 30 mu m long was observed.
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Dates et versions

hal-02959431 , version 1 (06-10-2020)

Identifiants

Citer

Martin Williams, Valérie Cornuault, Amir Irani, V. Vaughan Symonds, Jenny Malmström, et al.. Polysaccharide Structures in the Outer Mucilage of Arabidopsis Seeds Visualized by AFM. Biomacromolecules, 2020, 21 (4), pp.1450-1459. ⟨10.1021/acs.biomac.9b01756⟩. ⟨hal-02959431⟩
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