What is it about?
We investigated RecG, a bacterial protein that helps Escherichia coli deal with branched DNA structures that arise during chromosome replication and repair. Using fluorescently tagged RecG, we found that it forms spots in cells that coincide with markers of active DNA replication. We then changed amino acids near the protein’s C-terminus and found that one conserved arginine-tryptophan pair is important for this localisation, while the very end of the protein is crucial for DNA unwinding. The key surprise was that these roles are separable: mutations that disrupted localisation caused only a modest loss of repair capacity, whereas changes at the extreme end reduced unwinding without preventing DNA binding.
Featured Image
Why is it important?
RecG has been linked to bacterial genome maintenance, but the role of its structurally unresolved C-terminal region was not clear. Our study suggests that this small region contributes both to where RecG is positioned in the cell and to how effectively it remodels replication-fork and Holliday-junction DNA. This helps explain how seemingly minor changes at the end of RecG may affect DNA repair and viability in sensitive genetic backgrounds.
Perspectives
What stands out to us is how much could be learned from the final few amino acids of RecG, a part of the protein not visible in the available structure. By combining cell localisation, genetic tests and biochemical assays, we could separate effects on localisation, DNA binding and DNA unwinding. This gives a more precise view of how RecG’s C-terminus contributes to bacterial DNA replication and repair, without assuming that localisation alone defines function.
Dr. Christian J Rudolph
Brunel University
Read the Original
This page is a summary of: Cellular location and activity of Escherichia coli RecG proteins shed light on the function of its structurally unresolved C-terminus, Nucleic Acids Research, April 2014, Oxford University Press (OUP),
DOI: 10.1093/nar/gku228.
You can read the full text:
Contributors
The following have contributed to this page
