4PT2

Myxococcus xanthus encapsulin protein (EncA)

4PT2 の概要

• エントリーDOI: 10.2210/pdb4pt2/pdb
• EMDBエントリー: 5917
• 分子名称: Encapsulin protein (1 entity in total)
• 機能のキーワード: hk97 fold, shell protein, virus like particle
• 由来する生物種: Myxococcus xanthus
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 95075.93

構造登録者

Fontana, J.,Aksyuk, A.A.,Steven, A.C.,Hoiczyk, E. (登録日: 2014-03-10, 公開日: 2014-07-30, 最終更新日: 2024-02-28)

主引用文献

McHugh, C.A.,Fontana, J.,Nemecek, D.,Cheng, N.,Aksyuk, A.A.,Heymann, J.B.,Winkler, D.C.,Lam, A.S.,Wall, J.S.,Steven, A.C.,Hoiczyk, E.
A virus capsid-like nanocompartment that stores iron and protects bacteria from oxidative stress.
Embo J., 33:1896-1911, 2014

PubMed Abstract: Living cells compartmentalize materials and enzymatic reactions to increase metabolic efficiency. While eukaryotes use membrane-bound organelles, bacteria and archaea rely primarily on protein-bound nanocompartments. Encapsulins constitute a class of nanocompartments widespread in bacteria and archaea whose functions have hitherto been unclear. Here, we characterize the encapsulin nanocompartment from Myxococcus xanthus, which consists of a shell protein (EncA, 32.5 kDa) and three internal proteins (EncB, 17 kDa; EncC, 13 kDa; EncD, 11 kDa). Using cryo-electron microscopy, we determined that EncA self-assembles into an icosahedral shell 32 nm in diameter (26 nm internal diameter), built from 180 subunits with the fold first observed in bacteriophage HK97 capsid. The internal proteins, of which EncB and EncC have ferritin-like domains, attach to its inner surface. Native nanocompartments have dense iron-rich cores. Functionally, they resemble ferritins, cage-like iron storage proteins, but with a massively greater capacity (~30,000 iron atoms versus ~3,000 in ferritin). Physiological data reveal that few nanocompartments are assembled during vegetative growth, but they increase fivefold upon starvation, protecting cells from oxidative stress through iron sequestration.

PubMed: 25024436
DOI: 10.15252/embj.201488566

実験手法

ELECTRON MICROSCOPY (4.6 Å)