FtsZ filament structures in different nucleotide states reveal the mechanism of assembly dynamics

PLoS Biol. 2022 Mar 21;20(3):e3001497. doi: 10.1371/journal.pbio.3001497. eCollection 2022 Mar.

Abstract

Treadmilling protein filaments perform essential cellular functions by growing from one end while shrinking from the other, driven by nucleotide hydrolysis. Bacterial cell division relies on the primitive tubulin homolog FtsZ, a target for antibiotic discovery that assembles into single treadmilling filaments that hydrolyse GTP at an active site formed upon subunit association. We determined high-resolution filament structures of FtsZ from the pathogen Staphylococcus aureus in complex with different nucleotide analogs and cations, including mimetics of the ground and transition states of catalysis. Together with mutational and biochemical analyses, our structures reveal interactions made by the GTP γ-phosphate and Mg2+ at the subunit interface, a K+ ion stabilizing loop T7 for co-catalysis, new roles of key residues at the active site and a nearby crosstalk area, and rearrangements of a dynamic water shell bridging adjacent subunits upon GTP hydrolysis. We propose a mechanistic model that integrates nucleotide hydrolysis signaling with assembly-associated conformational changes and filament treadmilling. Equivalent assembly mechanisms may apply to more complex tubulin and actin cytomotive filaments that share analogous features with FtsZ.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / metabolism
  • Cytoskeletal Proteins* / metabolism
  • Guanosine Triphosphate / metabolism
  • Nucleotides*
  • Tubulin

Substances

  • Bacterial Proteins
  • Cytoskeletal Proteins
  • Nucleotides
  • Tubulin
  • Guanosine Triphosphate

Grant support

This work was funded by grants BFU2014-51823-R to JMA and BFU2017-87387-P and PID2020-116722GB-I00 to CFT, all funded by the Spanish Ministry of Science (MCIN), the Agencia Estatal de Investigación (AEI) and the European Regional Development Fund (ERDF). https://www.ciencia.gob.es/http://www.aei.gob.es/https://ec.europa.eu/regional_policy/en/funding/erdf/ The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.