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Nucleotide‐induced folding of cell division protein FtsZ from Staphylococcus aureus
Author(s) -
Huecas Sonia,
CanosaValls Alejandro J.,
AraújoBazán Lidia,
Ruiz Federico M.,
Laurents Douglas V.,
FernándezTornero Carlos,
Andreu José M.
Publication year - 2020
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.15235
Subject(s) - ftsz , gtp' , nucleotide , osmolyte , isothermal titration calorimetry , biochemistry , gtpase , dnaa , circular dichroism , biophysics , chemistry , guanosine diphosphate , biology , guanosine triphosphate , cell division , dna replication , dna , origin of replication , gene , cell , enzyme
The essential bacterial division protein FtsZ uses GTP binding and hydrolysis to assemble into dynamic filaments that treadmill around the Z‐ring, guiding septal wall synthesis and cell division. FtsZ is a structural homolog of tubulin and a target for discovering new antibiotics. Here, using FtsZ from the pathogen S. aureus (SaFtsZ), we reveal that, prior to assembly, FtsZ monomers require nucleotide binding for folding; this is possibly relevant to other mesophilic FtsZs. Apo‐SaFtsZ is essentially unfolded, as assessed by nuclear magnetic resonance and circular dichroism. Binding of GTP (≥ 1 m m ) dramatically shifts the equilibrium toward the active folded protein. Supportingly, SaFtsZ refolded with GDP crystallizes in a native structure. Apo‐SaFtsZ also folds with 3.4 m glycerol, enabling high‐affinity GTP binding ( K D 20 n m determined by isothermal titration calorimetry) similar to thermophilic stable FtsZ. Other stabilizing agents that enhance nucleotide binding include ethylene glycol, trimethylamine N‐oxide, and several bacterial osmolytes. High salt stabilizes SaFtsZ without bound nucleotide in an inactive twisted conformation. We identified a cavity behind the SaFtsZ‐GDP nucleotide‐binding pocket that harbors different small compounds, which is available for extended nucleotide‐replacing inhibitors. Furthermore, we devised a competition assay to detect any inhibitors that overlap the nucleotide site of SaFtsZ, or Escherichia coli FtsZ, employing osmolyte‐stabilized apo‐FtsZs and the specific fluorescence anisotropy change in mant ‐GTP upon dissociation from the protein. This robust assay provides a basis to screening for high‐affinity GTP‐replacing ligands, which combined with structural studies and phenotypic profiling should facilitate development of a next generation of FtsZ‐targeting antibacterial inhibitors.