8EMC

CryoEM characterization of BrxL -- a unique AAA+ phage restriction Factor.

8EMC の概要

• エントリーDOI: 10.2210/pdb8emc/pdb
• EMDBエントリー: 28244
• 分子名称: Protease Lon-related BREX system protein BrxL (1 entity in total)
• 機能のキーワード: phage restriction factor, aaa+ protein. brxl, antimicrobial protein
• 由来する生物種: Acinetobacter sp. NEB 394
• タンパク質・核酸の鎖数: 14
• 化学式量合計: 1059849.55

構造登録者

Shen, B.W.,Stoddard, B.L. (登録日: 2022-09-27, 公開日: 2023-02-01, 最終更新日: 2024-06-19)

主引用文献

Shen, B.W.,Doyle, L.A.,Werther, R.,Westburg, A.A.,Bies, D.P.,Walter, S.I.,Luyten, Y.A.,Morgan, R.D.,Stoddard, B.L.,Kaiser, B.K.
Structure, substrate binding and activity of a unique AAA+ protein: the BrxL phage restriction factor.
Nucleic Acids Res., 51:3513-3528, 2023

PubMed Abstract: Bacteriophage exclusion ('BREX') systems are multi-protein complexes encoded by a variety of bacteria and archaea that restrict phage by an unknown mechanism. One BREX factor, termed BrxL, has been noted to display sequence similarity to various AAA+ protein factors including Lon protease. In this study we describe multiple CryoEM structures of BrxL that demonstrate it to be a chambered, ATP-dependent DNA binding protein. The largest BrxL assemblage corresponds to a dimer of heptamers in the absence of bound DNA, versus a dimer of hexamers when DNA is bound in its central pore. The protein displays DNA-dependent ATPase activity, and ATP binding promotes assembly of the complex on DNA. Point mutations within several regions of the protein-DNA complex alter one or more in vitro behaviors and activities, including ATPase activity and ATP-dependent association with DNA. However, only the disruption of the ATPase active site fully eliminates phage restriction, indicating that other mutations can still complement BrxL function within the context of an otherwise intact BREX system. BrxL displays significant structural homology to MCM subunits (the replicative helicase in archaea and eukaryotes), implying that it and other BREX factors may collaborate to disrupt initiation of phage DNA replication.

PubMed: 36794719
DOI: 10.1093/nar/gkad083

実験手法

ELECTRON MICROSCOPY (3.6 Å)