RT Journal Article
SR Electronic
T1 Structural characterization of encapsulated ferritin provides insight into iron storage in bacterial nanocompartments
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 063495
DO 10.1101/063495
A1 Didi He
A1 Sam Hughes
A1 Sally Vanden-Hehir
A1 Atanas Georgiev
A1 Kirsten Altenbach
A1 Emma Tarrant
A1 C. Logan Mackay
A1 Kevin J. Waldron
A1 David J. Clarke
A1 Jon Marles-Wright
YR 2016
UL http://biorxiv.org/content/early/2016/07/12/063495.abstract
AB Ferritins are ubiquitous proteins that oxidise and store iron within a protein shell to protect cells from oxidative damage. We have characterized the structure and function of a new member of the ferritin superfamily that is sequestered within an encapsulin capsid. We show that this encapsulated ferritin (EncFtn) has two main alpha helices, which assemble in a metal dependent manner to form a ferroxidase centre at a dimer interface. EncFtn adopts an open decameric structure that is topologically distinct from other ferritins. While EncFtn acts as a ferroxidase, it cannot mineralize iron. Conversely, the encapsulin shell associates with iron, but is not enzymatically active, and we demonstrate that EncFtn must be housed within the encapsulin for iron storage. This encapsulin nanocompartment is widely distributed in bacteria and archaea and represents a distinct class of iron storage system where the oxidation and mineralization of iron are distributed between two proteins.