title: Insights into FlaI functions in archaeal motor assembly and motility from structures, conformations, and genetics.
abstract: 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.
authors: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors: Sophia
authors: S
authors: Reindl
authors: Abhrajyoti
authors: A
authors: Ghosh
authors: Gareth J
authors: GJ
authors: Williams
authors: Kerstin
authors: K
authors: Lassak
authors: Tomasz
authors: T
authors: Neiner
authors: Anna-Lena
authors: AL
authors: Henche
authors: Sonja-Verena
authors: SV
authors: Albers
authors: John A
authors: JA
authors: Tainer
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D005407:Flagella / Q000201:enzymology / Q000648:ultrastructure; D006868:Hydrolysis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D016945:Sulfolobus acidocaldarius / Q000502:physiology* / Q000648:ultrastructure; D013499:Surface Properties
chemical_list: D019843:Archaeal Proteins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases