The crystal structure of Giardia duodenalis 14-3-3 in the apo form: when protein post-translational modifications make the difference.

Annarita Fiorillo, Daniele di Marino, Lucia Bertuccini, Allegra Via, Edoardo Pozio, Serena Camerini, Andrea Ilari, Marco Lalle

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11 Scopus citations


The 14-3-3s are a family of dimeric evolutionary conserved pSer/pThr binding proteins that play a key role in multiple biological processes by interacting with a plethora of client proteins. Giardia duodenalis is a flagellated protozoan that affects millions of people worldwide causing an acute and chronic diarrheal disease. The single giardial 14-3-3 isoform (g14-3-3), unique in the 14-3-3 family, needs the constitutive phosphorylation of Thr214 and the polyglycylation of its C-terminus to be fully functional in vivo. Alteration of the phosphorylation and polyglycylation status affects the parasite differentiation into the cyst stage. To further investigate the role of these post-translational modifications, the crystal structure of the g14-3-3 was solved in the unmodified apo form. Oligomers of g14-3-3 were observed due to domain swapping events at the protein C-terminus. The formation of filaments was supported by TEM. Mutational analysis, in combination with native PAGE and chemical cross-linking, proved that polyglycylation prevents oligomerization. In silico phosphorylation and molecular dynamics simulations supported a structural role for the phosphorylation of Thr214 in promoting target binding. Our findings highlight unique structural features of g14-3-3 opening novel perspectives on the evolutionary history of this protein family and envisaging the possibility to develop anti-giardial drugs targeting g14-3-3.
Original languageEnglish (US)
Pages (from-to)e92902
JournalPLoS ONE
Issue number3
StatePublished - Mar 21 2014
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUK-I1-012-43
Acknowledgements: This study has been partially supported by the Italian Ministero dell'Istruzione, dell'Universita e della Ricerca (FIRB grant RBFR08F41U), Istituto Superiore di Sanita (1APC/1303/2011), Fondazione Istituto Italiano di Tecnologia (IIT), (grant "Tecniche di Bioinformatica strutturale: Modellizzazione di proteine, docking e simulazione di dinamica molecolare), and the King Abdullah University of Science and Technology (KAUST, grant KUK-I1-012-43). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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