6CG8

Structure of C. crescentus GapR-DNA

Summary for 6CG8

• Entry DOI: 10.2210/pdb6cg8/pdb
• Descriptor: UPF0335 protein B7Z12_12435, DNA (5'-D(*TP*TP*AP*AP*AP*AP*TP*TP*AP*AP*A)-3'), DNA (5'-D(*TP*TP*TP*AP*AP*TP*TP*TP*TP*AP*A)-3'), ... (4 entities in total)
• Functional Keywords: gapr, dna binding, dna binding protein, dna binding protein-dna complex, dna binding protein/dna
• Biological source: Caulobacter vibrioides (Caulobacter crescentus); More
• Total number of polymer chains: 6
• Total formula weight: 42675.12

Authors

Schumacher, M.A. (deposition date: 2018-02-19, release date: 2018-09-26, Last modification date: 2024-03-13)

Primary citation

Guo, M.S.,Haakonsen, D.L.,Zeng, W.,Schumacher, M.A.,Laub, M.T.
A Bacterial Chromosome Structuring Protein Binds Overtwisted DNA to Stimulate Type II Topoisomerases and Enable DNA Replication.
Cell, 175:583-, 2018

PubMed Abstract: When DNA is unwound during replication, it becomes overtwisted and forms positive supercoils in front of the translocating DNA polymerase. Unless removed or dissipated, this superhelical tension can impede replication elongation. Topoisomerases, including gyrase and topoisomerase IV in bacteria, are required to relax positive supercoils ahead of DNA polymerase but may not be sufficient for replication. Here, we find that GapR, a chromosome structuring protein in Caulobacter crescentus, is required to complete DNA replication. GapR associates in vivo with positively supercoiled chromosomal DNA, and our biochemical and structural studies demonstrate that GapR forms a dimer-of-dimers that fully encircles overtwisted DNA. Further, we show that GapR stimulates gyrase and topo IV to relax positive supercoils, thereby enabling DNA replication. Analogous chromosome structuring proteins that locate to the overtwisted DNA in front of replication forks may be present in other organisms, similarly helping to recruit and stimulate topoisomerases during DNA replication.

PubMed: 30220456
DOI: 10.1016/j.cell.2018.08.029

Experimental method

X-RAY DIFFRACTION (2.299 Å)