4gfl | pdb_00004gfl
NO mechanism, slma
Structural highlights
FunctionSLMA_KLEP3 Required for nucleoid occlusion (NO) phenomenon, which prevents Z-ring formation and cell division over the nucleoid. Acts as a DNA-associated cell division inhibitor that binds simultaneously chromosomal DNA and FtsZ, and disrupts the assembly of FtsZ polymers. SlmA-DNA-binding sequences (SBS) are dispersed on non-Ter regions of the chromosome, preventing FtsZ polymerization at these regions (By similarity). Publication Abstract from PubMedThe spatial and temporal control of Filamenting temperature sensitive mutant Z (FtsZ) Z-ring formation is crucial for proper cell division in bacteria. In Escherichia coli, the synthetic lethal with a defective Min system (SlmA) protein helps mediate nucleoid occlusion, which prevents chromosome fragmentation by binding FtsZ and inhibiting Z-ring formation over the nucleoid. However, to perform its function, SlmA must be bound to the nucleoid. To deduce the basis for this chromosomal requirement, we performed biochemical, cellular, and structural studies. Strikingly, structures show that SlmA dramatically distorts DNA, allowing it to bind as an orientated dimer-of-dimers. Biochemical data indicate that SlmA dimer-of-dimers can spread along the DNA. Combined structural and biochemical data suggest that this DNA-activated SlmA oligomerization would prevent FtsZ protofilament propagation and bundling. Bioinformatic analyses localize SlmA DNA sites near membrane-tethered chromosomal regions, and cellular studies show that SlmA inhibits FtsZ reservoirs from forming membrane-tethered Z rings. Thus, our combined data indicate that SlmA DNA helps block Z-ring formation over chromosomal DNA by forming higher-order protein-nucleic acid complexes that disable FtsZ filaments from coalescing into proper structures needed for Z-ring creation. SlmA forms a higher-order structure on DNA that inhibits cytokinetic Z-ring formation over the nucleoid.,Tonthat NK, Milam SL, Chinnam N, Whitfill T, Margolin W, Schumacher MA Proc Natl Acad Sci U S A. 2013 Jun 10. PMID:23754405[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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