GapR is a nucleoid-associated protein (NAP) critical for cellular function in Caulobacter crescentus (also known as Caulobacter vibrioides). Loss of GapR causes severe defects in growth, cell division, DNA replication, and chromosome segregation [2,3 ...
GapR is a nucleoid-associated protein (NAP) critical for cellular function in Caulobacter crescentus (also known as Caulobacter vibrioides). Loss of GapR causes severe defects in growth, cell division, DNA replication, and chromosome segregation [2,3]. This is a DNA-binding protein which has mainly an alpha-helical secondary structure. In the absence of DNA, GapR is a dimer, with each monomer folded into two extended alpha-helices, while in the presence of DNA, GapR forms a tetramer, with the C-terminal alpha-helix of each monomer reorganised into two shorter helices, which allows GapR to encircle the DNA [1,2,3]. This is the DNA-binding domain of GapR from Caulobacter crescentus and related sequences. This domain is not only highly conserved in Alphaproteobacteria, it is also present in cyanobacteria, firmicutes, planctomycetes, actinobacteria, and even archaea and eukaryotes, possibly through horizontal gene transfer. This domain is also found in phages, in which it is associated to DNA-related processes [2].
