Abstract
Legume lectins have been widely studied and applied for many purposes in
the last few decades, but many of their physiological aspects remain
elusive. The Diocleinae legume subtribe, which includes intensively
explored lectins, such as ConA, presents an unusual and extensive
post-translational process which results in minor alterations in protein
structure, in turn making its function elusive. Despite previous reports
about Diocleinae precursor activity, no structural or functional
analyses have ever been carried out to understand the impacts of
post-translational processing relative to lectin structure and binding
specificity. Here we analyzed the functionality of a non glycosylated,
recombinantly expressed lectin precursor from Dioclea grandiflora
through inhibition assays, corroborating the experimental data with
structural information generated by molecular modeling, docking
calculations and molecular dynamics simulations. We demonstrate that
Diocleinae precursors are active and share the same carbohydrate
specificity as mature lectins. At the same time, however, subtle
structural alterations were detected and mostly result in an
``incomplete'' functionality of the precursor, as consequence of an
immature binding site and an unstructured tetramer interface, affecting
carbohydrate binding and oligomer formation, respectively. (C) 2016
Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire
(SFBBM). All rights reserved.
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