Structural insights into peptidoglycan hydrolysis by the FtsEX system in Escherichia coli during cell division.

High-resolution structures of Escherichia coli FtsEX show ATP-dependent stabilization and, upon EnvC binding, a symmetrical Eco FtsEX conformation that accommodates EnvC asymmetry via flexible periplasmic loops.

• Why it matters: Septal peptidoglycan remodeling during cytokinesis requires precise coordination between FtsEX and EnvC, but the structural basis for PG degradation by FtsEX/EnvC in Escherichia coli remained unclear.
• What they did: The study combined biochemical assays with high-resolution structural determination of Eco FtsEX ± EnvC, plus negative-staining imaging of an Eco FtsEX/EnvC/AmiB complex.
• The result: EnvC binding markedly increases ATPase activity, and the elongated Eco FtsEX/EnvC/AmiB complex resembles Pseudomonas aeruginosa Pae FtsEX, suggesting conserved regulation of hydrolase activation for PG cleavage.