1vz0: Difference between revisions

Prokaryotic chromosomes and plasmids encode partitioning systems that are, required for DNA segregation at cell division. The plasmid partitioning, loci encode two proteins, ParA and ParB, and a cis-acting centromere-like, site denoted parS. The chromosomally encoded homologues of ParA and ParB, Soj and Spo0J, play an active role in chromosome segregation during, bacterial cell division and sporulation. Spo0J is a DNA-binding protein, that binds to parS sites in vivo. We have solved the X-ray crystal, structure of a C-terminally truncated Spo0J (amino acids 1-222) from, Thermus thermophilus to 2.3 A resolution by multiwavelength anomalous, dispersion. It is a DNA-binding protein with structural similarity to the, helix-turn-helix (HTH) motif of the lambda repressor DNA-binding domain., The crystal structure is an antiparallel dimer with the recognition, alpha-helices of the HTH motifs of each monomer separated by a distance of, 34 A corresponding to the length of the helical repeat of B-DNA., Sedimentation velocity and equilibrium ultracentrifugation studies show, that full-length Spo0J exists in a monomer-dimer equilibrium in solution, and that Spo0J1-222 is exclusively monomeric. Sedimentation of the, C-terminal domain of Spo0J shows it to be exclusively dimeric, confirming, that the C-terminus is the primary dimerization domain. We hypothesize, that the C-terminus mediates dimerization of Spo0J, thereby effectively, increasing the local concentration of the N-termini, which most probably, dimerize, as shown by our structure, upon binding to a cognate parS site.

1VZ0 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus] with CO and MG as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1VZ0 OCA].  

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