5YEU

Structural and mechanistic analyses reveal a unique Cas4-like protein in the mimivirus virophage resistance element system

5YEU の概要

• エントリーDOI: 10.2210/pdb5yeu/pdb
• 分子名称: Uncharacterized protein R354, MAGNESIUM ION (3 entities in total)
• 機能のキーワード: mimivire, cas4-like, nuclease, ribosomal protein, nuclear protein
• 由来する生物種: Acanthamoeba polyphaga mimivirus (APMV)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 92081.21

構造登録者

Dou, C.,Yu, M.J.,Gu, Y.J.,Cheng, W. (登録日: 2017-09-19, 公開日: 2018-07-25, 最終更新日: 2024-03-27)

主引用文献

Dou, C.,Yu, M.,Gu, Y.,Wang, J.,Yin, K.,Nie, C.,Zhu, X.,Qi, S.,Wei, Y.,Cheng, W.
Structural and Mechanistic Analyses Reveal a Unique Cas4-like Protein in the Mimivirus Virophage Resistance Element System.
Iscience, 3:1-10, 2018

PubMed Abstract: A clustered regularly interspaced short palindromic repeats (CRISPR)-like "mimivirus virophage resistance element" (MIMIVIRE) system, which contains specific cascade genes and a CRISPR array against virophages, was reported in mimiviruses. An essential component of the MIMIVIRE system is R354, encoding a nuclease and a likely functional homolog of Cas4. Here we show that R354 is a dual nuclease with both exonuclease and endonuclease activities. Structural analysis revealed that the catalytic core domain of R354 is similar to those of Cas4 and ? exonuclease despite their low sequence identity. R354 forms a homodimer that is important for its exonuclease but not endonuclease activity. Structural comparisons between the active and semi-active states of R354 demonstrated that an activation loop adjacent to the catalytic site is critical for enzymatic activity. Overall, the results suggest that R354 belongs to a novel MIMIVIRE system involved in innate virus immunity and provides a template for the identification of new CRISPR systems in other species.

PubMed: 30428313
DOI: 10.1016/j.isci.2018.04.001

実験手法

X-RAY DIFFRACTION (3.001 Å)