Cryo-EM structure of gas vesicles for buoyancy-controlled motility

Gas vesicles are gas-filled nanocompartments that allow a diverse group of bacteria and archaea to control their buoyancy. The molecular basis of their properties and assembly remains unclear. Here, we report the 3.2 Å cryo-EM structure of the gas vesicle shell made from the structural protein GvpA that self-assembles into hollow helical cylinders closed off by cone-shaped tips. Two helical half shells connect through a characteristic arrangement of GvpA monomers, suggesting a mechanism of gas vesicle biogenesis. The fold of GvpA features a corrugated wall structure typical for force-bearing thin-walled cylinders. Small pores enable gas molecules to diffuse across the shell, while the exceptionally hydrophobic interior surface effectively repels water. Comparative structural analysis confirms the evolutionary conservation of gas vesicle assemblies and demonstrates molecular features of shell reinforcement by GvpC. Our findings will further research into gas vesicle biology and facilitate molecular engineering of gas vesicles for ultrasound imaging. [Display omitted] •3.2 Å cryo-EM structure of microbial gas vesicles reveals atomic model of vesicle shell•The structure explains the molecular basis of selective permeability and vesicle growth•Fold and assembly are highly conserved between evolutionarily distant species•Binding interface and geometry of secondary structural protein GvpC are identified Cryo-EM structure of the gas vesicle shell provides insights into the evolutionarily conserved mechanistic basis of gas vesicle biogenesis and selective permeability.