ジャーナル: Proc Natl Acad Sci U S A / 年: 2018 タイトル: Cryo-EM reconstruction of AlfA from reveals the structure of a simplified actin-like filament at 3.4-Å resolution. 著者: Andrzej Szewczak-Harris / Jan Löwe / 要旨: Low copy-number plasmid pLS32 of subsp. contains a partitioning system that ensures segregation of plasmid copies during cell division. The partitioning locus comprises actin-like protein AlfA, ...Low copy-number plasmid pLS32 of subsp. contains a partitioning system that ensures segregation of plasmid copies during cell division. The partitioning locus comprises actin-like protein AlfA, adaptor protein AlfB, and the centromeric sequence Similar to the ParMRC partitioning system from plasmid R1, AlfA filaments form actin-like double helical filaments that arrange into an antiparallel bipolar spindle, which attaches its growing ends to sister plasmids through interactions with AlfB and Because, compared with ParM and other actin-like proteins, AlfA is highly diverged in sequence, we determined the atomic structure of nonbundling AlfA filaments to 3.4-Å resolution by cryo-EM. The structure reveals how the deletion of subdomain IIB of the canonical actin fold has been accommodated by unique longitudinal and lateral contacts, while still enabling formation of left-handed, double helical, polar and staggered filaments that are architecturally similar to ParM. Through cryo-EM reconstruction of bundling AlfA filaments, we obtained a pseudoatomic model of AlfA doublets: the assembly of two filaments. The filaments are antiparallel, as required by the segregation mechanism, and exactly antiphasic with near eightfold helical symmetry, to enable efficient doublet formation. The structure of AlfA filaments and doublets shows, in atomic detail, how deletion of an entire domain of the actin fold is compensated by changes to all interfaces so that the required properties of polymerization, nucleotide hydrolysis, and antiparallel doublet formation are retained to fulfill the system's biological raison d'être.
履歴
登録
2017年12月14日
登録サイト: PDBE / 処理サイト: PDBE
改定 1.0
2018年4月11日
Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: EM metadata / Data content type: EM metadata / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: FSC / Data content type: FSC / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: Image / Data content type: Image / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: Primary map / Data content type: Primary map / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: EM metadata / Data content type: EM metadata / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: FSC / Data content type: FSC / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: Image / Data content type: Image / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: Primary map / Data content type: Primary map / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: EM metadata / Data content type: EM metadata / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: FSC / Data content type: FSC / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: Image / Data content type: Image / Provider: repository / タイプ: Initial release
改定 1.0
2018年4月11日
Data content type: Primary map / Data content type: Primary map / Provider: repository / タイプ: Initial release
Data content type: EM metadata / Data content type: EM metadata / EM metadata / Group: Data processing / Experimental summary / Data content type: EM metadata / EM metadata / カテゴリ: em_admin / em_software / Data content type: EM metadata / EM metadata / Item: _em_admin.last_update / _em_software.name