4IHQ: Archaellum Assembly Atpase Flai Bound To Adp

Superfamily ATPases in type IV pili, type 2 secretion, and archaella (formerly archaeal flagella) employ similar sequences for distinct biological processes. Here, we structurally and functionally characterize prototypical superfamily ATPase FlaI in Sulfolobus acidocaldarius, showing FlaI activities in archaeal swimming-organelle assembly and movement. X-ray scattering data of FlaI in solution and crystal structures with and without nucleotide reveal a hexameric crown assembly with key cross-subunit interactions. Rigid building blocks form between N-terminal domains (points) and neighboring subunit C-terminal domains (crown ring). Upon nucleotide binding, these six cross-subunit blocks move with respect to each other and distinctly from secretion and pilus ATPases. Crown interactions and conformations regulate assembly, motility, and force direction via a basic-clamp switching mechanism driving conformational changes between stable, backbone-interconnected moving blocks. Collective structural and mutational results identify in vivo functional components for assembly and motility, phosphate-triggered rearrangements by ATP hydrolysis, and molecular predictors for distinct ATPase superfamily functions.
PDB ID: 4IHQDownload
MMDB ID: 108200
PDB Deposition Date: 2012/12/19
Updated in MMDB: 2013/05
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 4IHQ: hexameric; determined by author and by software (PISA)
Molecular Components in 4IHQ
Label Count Molecule
Proteins (6 molecules)
Flai Atpase
Molecule annotation
Chemicals (18 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB