Structural insights into ATP hydrolysis by the MoxR ATPase RavA and the LdcI-RavA cage-like complex

Matthew Jessop (1) , Benoît Arragain (1) , Roger Miras (2) , Angélique Fraudeau (1) , Karine Huard (1) , Maria Bacia-Verloop (1) , Patrice Catty (2) , Jan Felix (1) , Hélène Malet (1) , Irina Gutsche (1)

1 IBS MICA - Groupe Imagerie microscopique d'assemblages complexes / Microscopic Imaging of complex Assemblies group
2 BioMet - Biologie des Métaux

The hexameric MoxR AAA+ ATPase RavA and the decameric lysine decarboxylase LdcI form a 3.3 MDa cage, proposed to assist assembly of specific respiratory complexes in E. coli. Here, we show that inside the LdcI-RavA cage, RavA hexamers adopt an asymmetric spiral conformation in which the nucleotide-free seam is constrained to two opposite orientations. Cryo-EM reconstructions of free RavA reveal two co-existing structural states: an asymmetric spiral, and a flat C2-symmetric closed ring characterised by two nucleotide-free seams. The closed ring RavA state bears close structural similarity to the pseudo two-fold symmetric crystal structure of the AAA+ unfoldase ClpX, suggesting a common ATPase mechanism. Based on these structures, and in light of the current knowledge regarding AAA+ ATPases, we propose different scenarios for the ATP hydrolysis cycle of free RavA and the LdcI-RavA cage-like complex, and extend the comparison to other AAA+ ATPases of clade 7.

Domaines: Biologie structurale [q-bio.BM]; Bactériologie

Matthew Jessop, Benoît Arragain, Roger Miras, Angélique Fraudeau, Karine Huard, et al.. Structural insights into ATP hydrolysis by the MoxR ATPase RavA and the LdcI-RavA cage-like complex. Communications Biology, 2020, 3 (1), pp.46. ⟨10.1038/s42003-020-0772-0⟩. ⟨hal-02473206⟩