title: An amyloid organelle, solid-state NMR evidence for cross-β assembly of gas vesicles.
abstract: Functional amyloids have been identified in a wide range of organisms, taking on a variety of biological roles and being controlled by remarkable mechanisms of directed assembly. Here, we report that amyloid fibrils constitute the ribs of the buoyancy organelles of Anabaena flos-aquae. The walls of these gas-filled vesicles are known to comprise a single protein, GvpA, arranged in a low pitch helix. However, the tertiary and quaternary structures have been elusive. Using solid-state NMR correlation spectroscopy we find detailed evidence for an extended cross-β structure. This amyloid assembly helps to account for the strength and amphiphilic properties of the vesicle wall. Buoyancy organelles thus dramatically extend the scope of known functional amyloids.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Marvin J
authors.initials: MJ
authors.lastname: Bayro
authors.forename: Eugenio
authors.initials: E
authors.lastname: Daviso
authors.forename: Marina
authors.initials: M
authors.lastname: Belenky
authors.forename: Robert G
authors.initials: RG
authors.lastname: Griffin
authors.forename: Judith
authors.initials: J
authors.lastname: Herzfeld
mesh_terms: D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism; D046869:Dolichospermum flos-aquae / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D015388:Organelles / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000682:Amyloid; D011506:Proteins; C038524:gas vesicle protein