@article {He063495, author = {Didi He and Sam Hughes and Sally Vanden-Hehir and Atanas Georgiev and Kirsten Altenbach and Emma Tarrant and C. Logan Mackay and Kevin J. Waldron and David J. Clarke and Jon Marles-Wright}, title = {Structural characterization of encapsulated ferritin provides insight into iron storage in bacterial nanocompartments}, elocation-id = {063495}, year = {2016}, doi = {10.1101/063495}, publisher = {Cold Spring Harbor Laboratory}, abstract = {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.}, URL = {https://www.biorxiv.org/content/early/2016/07/12/063495}, eprint = {https://www.biorxiv.org/content/early/2016/07/12/063495.full.pdf}, journal = {bioRxiv} }