RT Journal Article
SR Electronic
T1 Cryo-EM structure of gas vesicles for buoyancy-controlled motility
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.05.08.489936
DO 10.1101/2022.05.08.489936
A1 Stefan T. Huber
A1 Dion Terwiel
A1 Wiel H. Evers
A1 David Maresca
A1 Arjen J. Jakobi
YR 2022
UL http://biorxiv.org/content/early/2022/05/09/2022.05.08.489936.abstract
AB Gas vesicles allow a diverse group of bacteria and archaea to move in the water column by controlling their buoyancy (1). These gas-filled cellular nanocompartments are formed by up to micrometers long protein shells that are permeable only to gas. The molecular basis of their unique properties and mechanism of assembly remains unknown. Here, we solve the 3.2 Å cryo-EM structure of the B.megaterium gas vesicle shell made from the structural protein GvpA that self-assembles into hollow helical cylinders closed off by cone-shaped tips. Remarkably, the unique fold adopted by GvpA generates a corrugated cylinder surface typically found in force-bearing thin-walled structures. We identified pores in the vesicle wall that enable gas molecules to freely diffuse in and out of the GV shell, while the exceptionally hydrophobic interior surface effectively repels water. Our results show that gas vesicles consist of two helical half-shells connected through a unique arrangement of GvpA monomers, suggesting a mechanism of gas vesicle biogenesis. Comparative structural analysis confirms the evolutionary conservation of gas vesicle assemblies and reveals molecular details of how the secondary structural protein GvpC reinforces the GvpA shell. Our findings provide a structural framework that will further research into the biology of gas vesicles, and enable rational molecular engineering to harness their unique properties for acoustic imaging (2, 3).Competing Interest StatementThe authors have declared no competing interest.