6R24

The structure of a Ty3 retrotransposon icosahedral capsid

6R24 の概要

• エントリーDOI: 10.2210/pdb6r24/pdb
• EMDBエントリー: 4709
• 分子名称: Transposon Ty3-I Gag-Pol polyprotein (1 entity in total)
• 機能のキーワード: ty3, retrotransposon, retrovirus, capsid, gag polyprotein, virus like particle
• 由来する生物種: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast)
• タンパク質・核酸の鎖数: 9
• 化学式量合計: 327441.34

構造登録者

Dodonova, S.O.,Prinz, S.,Bilanchone, V.,Sandmeyer, S.,Briggs, J.A.G. (登録日: 2019-03-15, 公開日: 2019-05-08, 最終更新日: 2024-05-15)

主引用文献

Dodonova, S.O.,Prinz, S.,Bilanchone, V.,Sandmeyer, S.,Briggs, J.A.G.
Structure of the Ty3/Gypsy retrotransposon capsid and the evolution of retroviruses.
Proc.Natl.Acad.Sci.USA, 116:10048-10057, 2019

PubMed Abstract: Retroviruses evolved from long terminal repeat (LTR) retrotransposons by acquisition of envelope functions, and subsequently reinvaded host genomes. Together, endogenous retroviruses and LTR retrotransposons represent major components of animal, plant, and fungal genomes. Sequences from these elements have been exapted to perform essential host functions, including placental development, synaptic communication, and transcriptional regulation. They encode a Gag polypeptide, the capsid domains of which can oligomerize to form a virus-like particle. The structures of retroviral capsids have been extensively described. They assemble an immature viral particle through oligomerization of full-length Gag. Proteolytic cleavage of Gag results in a mature, infectious particle. In contrast, the absence of structural data on LTR retrotransposon capsids hinders our understanding of their function and evolutionary relationships. Here, we report the capsid morphology and structure of the archetypal Gypsy retrotransposon Ty3. We performed electron tomography (ET) of immature and mature Ty3 particles within cells. We found that, in contrast to retroviruses, these do not change size or shape upon maturation. Cryo-ET and cryo-electron microscopy of purified, immature Ty3 particles revealed an irregular fullerene geometry previously described for mature retrovirus core particles and a tertiary and quaternary arrangement of the capsid (CA) C-terminal domain within the assembled capsid that is conserved with mature HIV-1. These findings provide a structural basis for studying retrotransposon capsids, including those domesticated in higher organisms. They suggest that assembly via a structurally distinct immature capsid is a later retroviral adaptation, while the structure of mature assembled capsids is conserved between LTR retrotransposons and retroviruses.

PubMed: 31036670
DOI: 10.1073/pnas.1900931116

実験手法

ELECTRON MICROSCOPY (7.5 Å)