Quaternary association in β-prism I fold plant lectins: Insights from X-ray crystallography, modelling and molecular dynamics.
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Date
2011-12
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Abstract
Dimeric banana lectin and calsepa, tetrameric artocarpin and octameric heltuba are mannose-specific β-prism I fold
lectins of nearly the same tertiary structure. MD simulations on individual subunits and the oligomers provide
insights into the changes in the structure brought about in the protomers on oligomerization, including swapping of
the N-terminal stretch in one instance. The regions that undergo changes also tend to exhibit dynamic flexibility
during MD simulations. The internal symmetries of individual oligomers are substantially retained during the
calculations. Energy minimization and simulations were also carried out on models using all possible oligomers by
employing the four different protomers. The unique dimerization pattern observed in calsepa could be traced to
unique substitutions in a peptide stretch involved in dimerization. The impossibility of a specific mode of
oligomerization involving a particular protomer is often expressed in terms of unacceptable steric contacts or
dissociation of the oligomer during simulations. The calculations also led to a rationale for the observation of a
heltuba tetramer in solution although the lectin exists as an octamer in the crystal, in addition to providing insights
into relations among evolution, oligomerization and ligand binding.
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Carbohydrate binding, MD simulation, molecular evolution, protein folding, protein–protein interaction, variability in quaternary structure
Citation
Sharma Alok, Vijayan Mamannamana. Quaternary association in β-prism I fold plant lectins: Insights from X-ray crystallography, modelling and molecular dynamics. Journal of Biosciences. 2011 Dec; 36 (5): 793-808.