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== Publication Abstract from PubMed ==
== Publication Abstract from PubMed ==
Conjugative plasmid transfer is the most important route for the spread of resistance and virulence genes among bacteria. Consequently, bacteria carrying conjugative plasmids are a substantial threat to human health, especially hospitalized patients. Whilst detailed information about the process has been obtained for Gram-negative type-4 secretion systems, little is known about the corresponding mechanisms in Gram-positive (G+) bacteria. The successful purification and crystallization of the putative transfer protein TraN from the G+ conjugative model plasmid pIP501 of Enterococcus faecalis are presented. Native crystals diffracted to 1.8 A resolution on a synchrotron beamline. The crystals belonged to space group P2(1), with unit-cell parameters a=32.88, b=54.94, c=57.71 A, beta=91.89 degrees and two molecules per asymmetric unit.
Conjugative transfer through type IV secretion multiprotein complexes is the most important means of spreading antimicrobial resistance. Plasmid pIP501, frequently found in clinical Enterococcus faecalis and Enterococcus faecium isolates, is the first Gram-positive (G+) conjugative plasmid for which self-transfer to Gram-negative (G-) bacteria has been demonstrated. The pIP501-encoded type IV secretion system (T4SS) protein TraN localizes to the cytoplasm and shows specific DNA binding. The specific DNA-binding site upstream of the pIP501 origin of transfer (oriT) was identified by a novel footprinting technique based on exonuclease digestion and sequencing, suggesting TraN to be an accessory protein of the pIP501 relaxase TraA. The structure of TraN was determined to 1.35 A resolution. It revealed an internal dimer fold with antiparallel beta-sheets in the centre and a helix-turn-helix (HTH) motif at both ends. Surprisingly, structurally related proteins (excisionases from T4SSs of G+ conjugative transposons and transcriptional regulators of the MerR family) resembling only one half of TraN were found. Thus, TraN may be involved in the early steps of pIP501 transfer, possibly triggering pIP501 TraA relaxase activity by recruiting the relaxosome to the assembled mating pore.


Crystallization and first data collection of the putative transfer protein TraN from the Gram-positive conjugative plasmid pIP501.,Goessweiner-Mohr N, Fercher C, Abajy MY, Grohmann E, Keller W Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012 Nov 1;68(Pt 11):1402-5., doi: 10.1107/S174430911204184X. Epub 2012 Oct 30. PMID:23143259<ref>PMID:23143259</ref>
Structure of the double-stranded DNA-binding type IV secretion protein TraN from Enterococcus.,Goessweiner-Mohr N, Eder M, Hofer G, Fercher C, Arends K, Birner-Gruenberger R, Grohmann E, Keller W Acta Crystallogr D Biol Crystallogr. 2014 Sep 1;70(Pt 9):2376-89. doi:, 10.1107/S1399004714014187. Epub 2014 Aug 29. PMID:25195751<ref>PMID:25195751</ref>


From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

Revision as of 08:49, 24 September 2014

Structure of the double-stranded DNA binding type IV secretion protein TraN from EnterococcusStructure of the double-stranded DNA binding type IV secretion protein TraN from Enterococcus

Structural highlights

4pm3 is a 2 chain structure. This structure supersedes the now removed PDB entry 4hh7. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:,
Related:4hh7
Resources:FirstGlance, OCA, RCSB, PDBsum

Publication Abstract from PubMed

Conjugative transfer through type IV secretion multiprotein complexes is the most important means of spreading antimicrobial resistance. Plasmid pIP501, frequently found in clinical Enterococcus faecalis and Enterococcus faecium isolates, is the first Gram-positive (G+) conjugative plasmid for which self-transfer to Gram-negative (G-) bacteria has been demonstrated. The pIP501-encoded type IV secretion system (T4SS) protein TraN localizes to the cytoplasm and shows specific DNA binding. The specific DNA-binding site upstream of the pIP501 origin of transfer (oriT) was identified by a novel footprinting technique based on exonuclease digestion and sequencing, suggesting TraN to be an accessory protein of the pIP501 relaxase TraA. The structure of TraN was determined to 1.35 A resolution. It revealed an internal dimer fold with antiparallel beta-sheets in the centre and a helix-turn-helix (HTH) motif at both ends. Surprisingly, structurally related proteins (excisionases from T4SSs of G+ conjugative transposons and transcriptional regulators of the MerR family) resembling only one half of TraN were found. Thus, TraN may be involved in the early steps of pIP501 transfer, possibly triggering pIP501 TraA relaxase activity by recruiting the relaxosome to the assembled mating pore.

Structure of the double-stranded DNA-binding type IV secretion protein TraN from Enterococcus.,Goessweiner-Mohr N, Eder M, Hofer G, Fercher C, Arends K, Birner-Gruenberger R, Grohmann E, Keller W Acta Crystallogr D Biol Crystallogr. 2014 Sep 1;70(Pt 9):2376-89. doi:, 10.1107/S1399004714014187. Epub 2014 Aug 29. PMID:25195751[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. ↑ Goessweiner-Mohr N, Eder M, Hofer G, Fercher C, Arends K, Birner-Gruenberger R, Grohmann E, Keller W. Structure of the double-stranded DNA-binding type IV secretion protein TraN from Enterococcus. Acta Crystallogr D Biol Crystallogr. 2014 Sep 1;70(Pt 9):2376-89. doi:, 10.1107/S1399004714014187. Epub 2014 Aug 29. PMID:25195751 doi:http://dx.doi.org/10.1107/S1399004714014187

4pm3, resolution 1.80Å

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