title: Structures of replication initiation proteins from staphylococcal antibiotic resistance plasmids reveal protein asymmetry and flexibility are necessary for replication.
abstract: Antibiotic resistance in pathogenic bacteria is a continual threat to human health, often residing in extrachromosomal plasmid DNA. Plasmids of the pT181 family are widespread and confer various antibiotic resistances to Staphylococcus aureus. They replicate via a rolling circle mechanism that requires a multi-functional, plasmid-encoded replication protein to initiate replication, recruit a helicase to the site of initiation and terminate replication after DNA synthesis is complete. We present the first atomic resolution structures of three such replication proteins that reveal distinct, functionally relevant conformations. The proteins possess a unique active site and have been shown to contain a catalytically essential metal ion that is bound in a manner distinct from that of any other rolling circle replication proteins. These structures are the first examples of the Rep_trans Pfam family providing insights into the replication of numerous antibiotic resistance plasmids from Gram-positive bacteria, Gram-negative phage and the mobilisation of DNA by conjugative transposons.
authors.affiliation: Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0FA, UK Stephen.carr@rc-harwell.ac.uk.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Carr
authors.affiliation: Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0FA, UK.
authors.forename: Simon E V
authors.initials: SE
authors.lastname: Phillips
authors.affiliation: Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Christopher D
authors.identifier: http://orcid.org/0000-0003-0316-6391
authors.initials: CD
authors.lastname: Thomas
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D020134:Catalytic Domain; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004265:DNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis* / Q000235:genetics; D004270:DNA, Circular / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D015870:Gene Expression; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013211:Staphylococcus aureus / Q000201:enzymology* / Q000235:genetics; D015534:Trans-Activators / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004270:DNA, Circular; D007527:Isoenzymes; D011994:Recombinant Proteins; D015534:Trans-Activators; C045264:replication initiator protein; D004265:DNA Helicases