Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAccurate DNA segregation is essential for genome transmission. Segregation of the prototypical F plasmid requires the centromere-binding protein SopB, the NTPase SopA and the sopC centromere. SopB displays an intriguing range of DNA-binding properties essential for partition; it binds sopC to form a partition complex, which recruits SopA, and it also coats DNA to prevent non-specific SopA-DNA interactions, which inhibits SopA polymerization. To understand the myriad functions of SopB, we determined a series of SopB-DNA crystal structures. SopB does not distort its DNA site and our data suggest that SopB-sopC forms an extended rather than wrapped partition complex with the SopA-interacting domains aligned on one face. SopB is a multidomain protein, which like P1 ParB contains an all-helical DNA-binding domain that is flexibly attached to a compact (beta(3)-alpha)(2) dimer-domain. Unlike P1 ParB, the SopB dimer-domain does not bind DNA. Moreover, SopB contains a unique secondary dimerization motif that bridges between DNA duplexes. Both specific and non-specific SopB-DNA bridging structures were observed. This DNA-linking function suggests a novel mechanism for in trans DNA spreading by SopB, explaining how it might mask DNA to prevent DNA-mediated inhibition of SopA polymerization. Insight into F plasmid DNA segregation revealed by structures of SopB and SopB-DNA complexes.,Schumacher MA, Piro KM, Xu W Nucleic Acids Res. 2010 Jul;38(13):4514-26. Epub 2010 Mar 17. PMID:20236989[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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