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Conformational features of crystal‐surface cellulose from higher plants
Author(s) -
Viëtor Remco J.,
Newman Roger H.,
Ha MarieAnn,
Apperley David C.,
Jarvis Michael C.
Publication year - 2002
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2002.01327.x
Subject(s) - hydrogen bond , crystallography , intramolecular force , molecule , crystal (programming language) , helix (gastropod) , crystal structure , ribbon , cellulose , glycosidic bond , residue (chemistry) , materials science , stereochemistry , chemistry , biology , organic chemistry , ecology , snail , computer science , composite material , programming language , enzyme
Summary Native cellulose in higher plants forms crystalline fibrils a few nm across, with a substantial fraction of their glucan chains at the surface. The accepted crystal structures feature a flat‐ribbon 2 1 helical chain conformation with every glucose residue locked to the next by hydrogen bonds from O‐3′ to O‐5 and from O‐2 to O‐6′. Using solid‐state NMR spectroscopy we show that the surface chains have a different C‐6 conformation so that O‐6 is not in the correct position for the hydrogen bond from O‐2. We also present evidence consistent with a model in which alternate glucosyl residues are transiently or permanently twisted away from the flat‐ribbon conformation of the chain, weakening the O‐3′ − 0‐5 hydrogen bond. Previous molecular modelling and the modelling studies reported here indicate that this ‘translational’ chain conformation is energetically feasible and does not preclude binding of the surface chains to the interior chains, because the surface chains share the axial repeat distance of the 2 1 helix. Reduced intramolecular hydrogen bonding allows the surface chains to form more hydrogen bonds to external molecules in textiles, wood, paper and the living plant.