Structure of the GDP-bound state of the SRP GTPase FlhF

Abstract

The GTPase FlhF, a signal recognition particle (SRP)-type enzyme, is pivotal for spatial–numerical control and bacterial flagella assembly across diverse species, including pathogens. This study presents the X-ray structure of FlhF in its GDP-bound state at a resolution of 2.28 Å. The structure exhibits the classical N- and G-domain fold, consistent with related SRP GTPases such as Ffh and FtsY. Comparative analysis with GTP-loaded FlhF elucidates the conformational changes associated with GTP hydrolysis. These topological reconfigurations are similarly evident in Ffh and FtsY, and play a pivotal role in regulating the functions of these hydrolases.

Polar confinement of a macromolecular machine by an SRP-type GTPase

“…Lower panel, left : X-ray structure of the FID domain of FlhF. Lower panel, right : X-ray structures of the FID domain (this study) and the GDP-bound state of the NG domain (PDB-ID: 8R9R 49 ;) from S. putrefaciens FlhF. The structurally uncharacterized linker is indicated by a dashed line, not drawn to scale.…”