A small protein-protein interaction domain common to KlcB and global regulators KorA and TrbA of promiscuous IncP plasmids11Edited by M. Belfort

This study presents the first complete sequence of an IncU plasmid, pFBAOT6. This plasmid was originally isolated from a strain of Aeromonas caviae from hospital effluent (Westmorland General Hospital, Kendal, United Kingdom) in September 1997 (G. Rhodes, G. Huys, J. Swings, P. McGann, M. Hiney, P. Smith, and R. W. Pickup, Appl. Environ. Microbiol. 66:3883-3890, 2000) and belongs to a group of related plasmids with global ubiquity. pFBAOT6 is 84,748 bp long and has 94 predicted coding sequences, only 12 of which do not have a possible function that has been attributed. Putative replication, maintenance, and transfer functions have been identified and are located in a region in the first 31 kb of the plasmid. The replication region is poorly understood but exhibits some identity at the protein level with replication proteins from the gram-positive bacteria Bacillus and Clostridium. The mating pair formation system is a virB homologue, type IV secretory pathway that is similar in its structural organization to the mating pair formation systems of the related broad-host-range (BHR) environmental plasmids pIPO2, pXF51, and pSB102 from plant-associated bacteria. Partitioning and maintenance genes are homologues of genes in IncP plasmids. The DNA transfer genes and the putative oriT site also exhibit high levels of similarity with those of plasmids pIPO2, pXF51, and pSB102. The genetic load region encompasses 54 kb, comprises the resistance genes, and includes a class I integron, an IS630 relative, and other transposable elements in a 43-kb region that may be a novel Tn1721-flanked composite transposon. This region also contains 24 genes that exhibit the highest levels of identity to chromosomal genes of several plant-associated bacteria. The features of the backbone of pFBAOT6 that are shared with this newly defined group of environmental BHR plasmids suggest that pFBAOT6 may be a relative of this group, but a relative that was isolated from a clinical bacterial environment rather than a plant-associated bacterial environment.

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“…In IncP plasmids klcA is part of the kilC operon (klcA-klcB-korC) and has no known function (7). In E. coli expression of the kilC operon (30).…”

Section: Resultsmentioning

confidence: 99%

Complete Nucleotide Sequence of the Conjugative Tetracycline Resistance Plasmid pFBAOT6, a Member of a Group of IncU Plasmids with Global Ubiquity

Rhodes

Parkhill

Bird

et al. 2004

Appl Environ Microbiol

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“…ParB binds to a specific centromerelike sequence (parS) on the chromosome forming a higher order nucleoprotein complex that is thought to pair the sister chromosomes/plasmids. ParA, an ATPase, binds to ParB and is thought to act as a motor, pulling or pushing two ParB-bound chromosomes apart to different poles of the bacterial cell (2)(3)(4).…”

mentioning

confidence: 99%

“…KorB binds simultaneously with RNA polymerase at promoters and interacts with it to prevent open complex formation (17). KorB can act upstream or downstream of the promoters and also at a distance (2)(3)(4)9). At all promoters, KorB acts cooperatively with a second repressor, either KorA, TrbA, or KorC, forming a regulatory network that coordinates expression of the operons on the plasmid (3,6,7,16).…”

mentioning

confidence: 99%

“…As the first structural description of a full-length ParB protein, we have reconstructed KorB from the known crystal structures using small angle x-ray scattering (SAXS) 5 and calculated an ensemble of conformations that the protein adopts in solution. This flexibility will be important for the protein's functional role in the cell enabling it to bind at different distances along DNA and to different binding partners (3)(4)(5)(6)9).…”

mentioning

confidence: 99%

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Order and Disorder in the Domain Organization of the Plasmid Partition Protein KorB

Rajasekar

Muntaha

Tame

et al. 2010

Journal of Biological Chemistry

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The plasmid partition protein KorB has a dual role: it is essential for the correct segregation of the low copy number broad host range RK2 plasmid while also being an important regulator of transcription. KorB belongs to the ParB family of proteins, and partitioning in RK2 has been studied as a simplified model of bacterial chromosome segregation. Structural information on full-length ParB proteins is limited, mainly due to the inability to grow crystals suitable for diffraction studies. We show, using CD and NMR, that KorB has regions of significant intrinsic disorder and hence it adopts a multiplicity of conformations in solution. The biophysical data are consistent with bioinformatic predictions based on the amino acid sequence that the N-terminal region and also the region between the central DNA-binding domain and the C-terminal dimerization domain are intrinsically disordered. We have used small angle x-ray scattering data to determine the ensemble of solution conformations for KorB and selected deletion mutants, based on models of the known domain structures. This conformational range of KorB is likely to be biologically required for DNA partitioning and for binding to a diverse set of partner proteins.

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“…In doing this, KorB normally works co-operatively with either KorA or TrbA [24], repressor proteins encoded in the central control operon and the trb region respectively. KorA and TrbA are composed of a closely related C-terminal dimerization domain (CTD), but different DNA-binding domains [25]. The CTD is important for the co-operative interaction with KorB [24,26].…”

Section: Global Regulation Of Plasmid Backbone Functionsmentioning

confidence: 99%

Transcription regulatory circuits in bacterial plasmids

Thomas

2006

Biochemical Society Transactions

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A small protein-protein interaction domain common to KlcB and global regulators KorA and TrbA of promiscuous IncP plasmids11Edited by M. Belfort

Cited by 19 publications

References 62 publications

Complete Nucleotide Sequence of the Conjugative Tetracycline Resistance Plasmid pFBAOT6, a Member of a Group of IncU Plasmids with Global Ubiquity

Complete Nucleotide Sequence of the Conjugative Tetracycline Resistance Plasmid pFBAOT6, a Member of a Group of IncU Plasmids with Global Ubiquity

Order and Disorder in the Domain Organization of the Plasmid Partition Protein KorB

Transcription regulatory circuits in bacterial plasmids

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