Molecular mechanism by which the nucleoid occlusion factor, SlmA, keeps cytokinesis in check.


Autoria(s): Tonthat, Nam Ky; Arold, Stefan T; Pickering, Brian F; Van Dyke, Michael W; Liang, Shoudan; Lu, Yue; Beuria, Tushar K; Margolin, William; Schumacher, Maria A
Data(s)

05/01/2011

Resumo

In Escherichia coli, cytokinesis is orchestrated by FtsZ, which forms a Z-ring to drive septation. Spatial and temporal control of Z-ring formation is achieved by the Min and nucleoid occlusion (NO) systems. Unlike the well-studied Min system, less is known about the anti-DNA guillotining NO process. Here, we describe studies addressing the molecular mechanism of SlmA (synthetic lethal with a defective Min system)-mediated NO. SlmA contains a TetR-like DNA-binding fold, and chromatin immunoprecipitation analyses show that SlmA-binding sites are dispersed on the chromosome except the Ter region, which segregates immediately before septation. SlmA binds DNA and FtsZ simultaneously, and the SlmA-FtsZ structure reveals that two FtsZ molecules sandwich a SlmA dimer. In this complex, FtsZ can still bind GTP and form protofilaments, but the separated protofilaments are forced into an anti-parallel arrangement. This suggests that SlmA may alter FtsZ polymer assembly. Indeed, electron microscopy data, showing that SlmA-DNA disrupts the formation of normal FtsZ polymers and induces distinct spiral structures, supports this. Thus, the combined data reveal how SlmA derails Z-ring formation at the correct place and time to effect NO.

Identificador

http://digitalcommons.library.tmc.edu/uthmed_docs/188

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3020112/?tool=pmcentrez

Publicador

DigitalCommons@The Texas Medical Center

Fonte

UT Medical School Journal Articles

Palavras-Chave #Bacterial Proteins #Base Sequence #Binding Sites #Carrier Proteins #Chromosomes #Bacterial #Crystallography #X-Ray #Cytokinesis #Cytoskeletal Proteins #DNA #Bacterial #Escherichia coli #Escherichia coli Proteins #Models #Molecular #Protein Binding #Protein Conformation #Protein Multimerization #Scattering #Small Angle #X-Ray Diffraction #Chromosomes, Bacterial #Crystallography, X-Ray #DNA, Bacterial #Models, Molecular #Scattering, Small Angle #Medicine and Health Sciences
Tipo

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