2xkb
Crystal structure of GDP-form protofilaments of Bacillus thuringiensis serovar israelensis TubZCrystal structure of GDP-form protofilaments of Bacillus thuringiensis serovar israelensis TubZ
Structural highlights
Publication Abstract from PubMedLow copy number plasmids often depend on accurate partitioning systems for their continued survival. Generally, such systems consist of a centromere-like region of DNA, a DNA-binding adaptor, and a polymerizing cytomotive filament. Together these components drive newly replicated plasmids to opposite ends of the dividing cell. The Bacillus thuringiensis plasmid pBToxis relies on a filament of the tubulin/FtsZ-like protein TubZ for its segregation. By combining crystallography and electron microscopy, we have determined the structure of this filament. We explain how GTP hydrolysis weakens the subunit-subunit contact and also shed light on the partitioning of the plasmid-adaptor complex. The double helical superstructure of TubZ filaments is unusual for tubulin-like proteins. Filaments of ParM, the actin-like partitioning protein, are also double helical. We suggest that convergent evolution shapes these different types of cytomotive filaments toward a general mechanism for plasmid separation. Filament structure of bacterial tubulin homologue TubZ.,Aylett CH, Wang Q, Michie KA, Amos LA, Lowe J Proc Natl Acad Sci U S A. 2010 Oct 25. PMID:20974911[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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