Christiansen, Gunna

Dueholm, Morten Simonsen

Finster, Kai

Larsen, Poul

Nielsen, Per Halkjær

Otzen, Daniel

Stenvang, Marcel R.

Archaea are well-recognized for their ability to thrive in extreme environments, although they can be found in virtually all habitats. Their adaptive success is linked to their unique cell envelopes, which often display extremely resistant to chemical and thermal denaturation and resist proteolysis by common proteases. These features are shared with a fascinating class of proteins polymers known as functional amyloids, which are defined by a characteristic cross-β-sheet structure and a nucleation dependent biogenesis. We have recently employed amyloid-specific conformation antibodies and biophysical techniques to show that the extracellular cell wall sheaths of the methanogenic archaea Methanosaeta and Methanospirillum are functional amyloid structures. Depolymerization of sheaths with formic acid and reducing agents and subsequent MS/MS analysis revealed that the sheaths are composed of a single major sheath protein (MspA). The amyloidogenic nature of MspA was confirmed by in vitro amyloid formation of recombinant MspA under a wide range of environmental conditions. This is the first report of a functional amyloid from the archaeal domain of life. The amyloid properties explain the extreme resistance of the sheath, the elastic properties that allow diffusible substrates to penetrate through expandable hoop boundaries, and how the sheaths are able to split and elongate outside the cell

The Tubular Sheaths Encasing Methanosaeta and Methanospirillum Filaments are Functional Amyloids

Abstract

Similar works

Full text

Available Versions

VBN