3OMY

Crystal structure of the pED208 TraM N-terminal domain

Summary for 3OMY

• Entry DOI: 10.2210/pdb3omy/pdb
• Descriptor: Protein traM, GLYCEROL, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: dna binding protein, dimer, bacterial conjugation, ribbon-helix-helix, transcriptional repressor, dna
• Biological source: Escherichia coli
• Cellular location: Cytoplasm: P33788
• Total number of polymer chains: 2
• Total formula weight: 12128.18

Authors

Wong, J.J.W.,Lu, J.,Edwards, R.A.,Frost, L.S.,Mark Glover, J.N. (deposition date: 2010-08-27, release date: 2011-05-25, Last modification date: 2023-09-06)

Primary citation

Wong, J.J.,Lu, J.,Edwards, R.A.,Frost, L.S.,Glover, J.N.
Structural basis of cooperative DNA recognition by the plasmid conjugation factor, TraM.
Nucleic Acids Res., 39:6775-6788, 2011

PubMed Abstract: The conjugative transfer of F-like plasmids such as F, R1, R100 and pED208, between bacterial cells requires TraM, a plasmid-encoded DNA-binding protein. TraM tetramers bridge the origin of transfer (oriT) to a key component of the conjugative pore, the coupling protein TraD. Here we show that TraM recognizes a high-affinity DNA-binding site, sbmA, as a cooperative dimer of tetramers. The crystal structure of the TraM-sbmA complex from the plasmid pED208 shows that binding cooperativity is mediated by DNA kinking and unwinding, without any direct contact between tetramers. Sequence-specific DNA recognition is carried out by TraM's N-terminal ribbon-helix-helix (RHH) domains, which bind DNA in a staggered arrangement. We demonstrate that both DNA-binding specificity, as well as selective interactions between TraM and the C-terminal tail of its cognate TraD mediate conjugation specificity within the F-like family of plasmids. The ability of TraM to cooperatively bind DNA without interaction between tetramers leaves the C-terminal TraM tetramerization domains free to make multiple interactions with TraD, driving recruitment of the plasmid to the conjugative pore.

PubMed: 21565799
DOI: 10.1093/nar/gkr296

Experimental method

X-RAY DIFFRACTION (1.3 Å)