Structure of Anabaena flos-aquae gas vesicles revealed by cryo-ET

Przemysław Dutka; Lauren Ann Metskas; Robert C Hurt; Hossein Salahshoor; Ting-Yu Wang; Dina Malounda; George J Lu; Tsui-Fen Chou; Mikhail G Shapiro; Grant J Jensen

doi:10.1016/j.str.2023.03.011

Structure of Anabaena flos-aquae gas vesicles revealed by cryo-ET

Structure. 2023 May 4;31(5):518-528.e6. doi: 10.1016/j.str.2023.03.011. Epub 2023 Apr 10.

Authors

Affiliations

¹ Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
² Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
³ Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA.
⁴ Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA.
⁵ Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
⁶ Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, Pasadena, CA 91125, USA. Electronic address: mikhail@caltech.edu.
⁷ Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; College of Physical and Mathematical Sciences, Brigham Young University, Provo, UT 84602, USA. Electronic address: grant_jensen@byu.edu.

Abstract

Gas vesicles (GVs) are gas-filled protein nanostructures employed by several species of bacteria and archaea as flotation devices to enable access to optimal light and nutrients. The unique physical properties of GVs have led to their use as genetically encodable contrast agents for ultrasound and MRI. Currently, however, the structure and assembly mechanism of GVs remain unknown. Here we employ cryoelectron tomography to reveal how the GV shell is formed by a helical filament of highly conserved GvpA subunits. This filament changes polarity at the center of the GV cylinder, a site that may act as an elongation center. Subtomogram averaging reveals a corrugated pattern of the shell arising from polymerization of GvpA into a β sheet. The accessory protein GvpC forms a helical cage around the GvpA shell, providing structural reinforcement. Together, our results help explain the remarkable mechanical properties of GVs and their ability to adopt different diameters and shapes.

Keywords: acoustic reporter genes; buoyancy; cryo-ET; gas vesicles; microbial motility; subtomogram averaging; ultrasound contrast agents.

Publication types

Research Support, Non-U.S. Gov't
Research Support, N.I.H., Extramural

MeSH terms

Anabaena* / chemistry
Anabaena* / metabolism
Archaea
Bacterial Proteins / chemistry
Dolichospermum flos-aquae* / metabolism

Substances

Bacterial Proteins

Abstract

Publication types

MeSH terms

Substances

Grants and funding