DOI: 10.1073/pnas.1716424115
论文题名: Cryo-EM reconstruction of AlfA from Bacillus subtilis reveals the structure of a simplified actin-like filament at 3.4-Å resolution
作者: Szewczak-Harris A. ; Löwe J.
刊名: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
出版年: 2018
卷: 115, 期: 13 起始页码: 3458
结束页码: 3463
语种: 英语
英文关键词: Actin
; Bacterial cytoskeleton
; Cryo-EM
; Helical reconstruction
; Plasmid segregation
Scopus关键词: AlfA protein
; bacterial protein
; plasmid DNA
; unclassified drug
; bacterial DNA
; bacterial protein
; actin filament
; Article
; Bacillus subtilis
; controlled study
; cryoelectron microscopy
; hydrolysis
; image reconstruction
; nonhuman
; plasmid
; polymerization
; priority journal
; protein structure
; actin filament
; Bacillus subtilis
; cryoelectron microscopy
; cytoskeleton
; metabolism
; molecular model
; plasmid
; procedures
; ultrastructure
; X ray crystallography
; Actin Cytoskeleton
; Bacillus subtilis
; Bacterial Proteins
; Cryoelectron Microscopy
; Crystallography, X-Ray
; Cytoskeleton
; DNA, Bacterial
; Models, Molecular
; Plasmids
英文摘要: Low copy-number plasmid pLS32 of Bacillus subtilis subsp. natto contains a partitioning system that ensures segregation of plasmid copies during cell division. The partitioning locus comprises actinlike protein AlfA, adaptor protein AlfB, and the centromeric sequence parN. Similar to the ParMRC partitioning system from Escherichia coli 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 parN. 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 antiphasicwith 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. © 2018 National Academy of Sciences. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/163730
Appears in Collections: 气候变化与战略
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作者单位: Szewczak-Harris, A., Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, United Kingdom; Löwe, J., Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, United Kingdom
Recommended Citation:
Szewczak-Harris A.,Löwe J.. Cryo-EM reconstruction of AlfA from Bacillus subtilis reveals the structure of a simplified actin-like filament at 3.4-Å resolution[J]. Proceedings of the National Academy of Sciences of the United States of America,2018-01-01,115(13)