Telomere resolution in the Lyme disease spirochete

Chaconas, George; Stewart, Philip E.; Tilly, Kit; Bono, James L.; Rosa, Patricia A.

doi:10.1093/emboj/20.12.3229

Cited by 95 publications

(125 citation statements)

References 39 publications

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“…Previously reported in vitro telomere resolution assays have used plasmid DNA substrates carrying replicated telomere targets (13-15, 21, 34). Although plasmid substrates are efficient, replicated Borrelia telomeres are unstable when cloned in Escherichia coli (11), making them inconvenient substrates. Plasmid substrates are also unsuitable for incorporation of modified nucleotides or for generation of heteroduplex substrates.…”

Section: Resultsmentioning

confidence: 99%

“…Previous work done on B. burgdorferi suggests bidirectional replication from an internal origin leading to the formation of a circular head-to-head, tail-to-tail dimer intermediate (10). Processing of the dimer junctions to generate linear hairpin ends in Borrelia occurs through a DNA breakage-andreunion event referred to as telomere resolution (3,(11)(12)(13). This process also occurs in the linear phages N15, PY54, and KO2, which also contain hairpin telomeres (14)(15)(16)(17)(18)(19)(20).…”

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confidence: 97%

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Mixing active-site components: A recipe for the unique enzymatic activity of a telomere resolvase

Bankhead

Chaconas

2004

Proc. Natl. Acad. Sci. U.S.A.

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The ResT protein, a telomere resolvase from Borrelia burgdorferi, processes replication intermediates into linear replicons with hairpin ends by using a catalytic mechanism similar to that for tyrosine recombinases and type IB topoisomerases. We have identified in ResT a hairpin binding region typically found in cut-and-paste transposases. We show that substitution of residues within this region results in a decreased ability of these mutants to catalyze telomere resolution. However, the mutants are capable of resolving heteroduplex DNA substrates designed to allow spontaneous destabilization and prehairpin formation. These findings support the existence of a hairpin binding region in ResT, the only known occurrence outside a transposase. The combination of transposaselike and tyrosine-recombinase-like domains found in ResT indicates the use of a composite active site and helps explain the unique breakage-and-reunion reaction observed with this protein. Comparison of the ResT sequence with other known telomere resolvases suggests that a hairpin binding motif is a common feature in this class of enzyme; the sequence motif also appears in the RAG recombinases. Finally, our data support a mechanism of action whereby ResT induces prehairpin formation before the DNA cleavage step.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 97%

Mixing active-site components: A recipe for the unique enzymatic activity of a telomere resolvase

Bankhead

Chaconas

2004

Proc. Natl. Acad. Sci. U.S.A.

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“…Passage of the replication forks through both of the hairpin telomeres would produce an inverted repeat circular dimer replication intermediate. The resulting replicated telomeres are processed by DNA breakage and reunion events (telomere resolution) that liberate the linear daughters from the presumed circular dimer intermediate (10). The enzymatic activity that performs telomere resolution is an essential cellular function provided by ResT, the product of the BBB03 locus of cp26 (11,12).…”

mentioning

confidence: 99%

“…Fig. 2, the asymmetric wt 1 -nick/OPN replicated telomere (rtel) was assembled with oligonucleotides OGCB 2 and 3, comprising the 70-bp side of the rtel, these oligonucleotides are reported in (10). OGCB 179 (5Ј-gatcCACTCTATACTAATAAAAAATT-A*T-3Ј) and OGCB 18 (5Ј-atatATAATTTTTTATTAGTATAGAGTG-3Ј) make up the 25-bp side of the rtel; the asterisk marks the position of the 5Ј-bridging OPN modification of the cleavage site.…”

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confidence: 99%

Uncoupling the Chemical Steps of Telomere Resolution by ResT

Kobryn

Burgin²,

Chaconas

2005

Journal of Biological Chemistry

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ResT is the telomere resolvase of the spirochete Borrelia burgdorferi, the causative agent of Lyme disease.ResT is an essential cellular function that processes replication intermediates to produce linear replicons terminated by covalently closed hairpin telomeres. ResT generates these hairpin telomeres in a reaction with mechanistic similarities to those catalyzed by type IB topoisomerases and tyrosine recombinases. We report here, that like most of the tyrosine recombinases, ResT requires interprotomer communication, likely in an in-line synapse, to activate reaction chemistry. Unlike the tyrosine recombinases, however, we infer that the cleavage and strand transfer reactions on the two sides of the replicated telomere occur nearly simultaneously. Nonetheless, the chemical steps of the forward and reverse reactions performed by ResT can occur in a non-concerted fashion (i.e. events on the two sides of the replicated telomere can occur independently). We propose that uncoupling of reaction completion on the two sides of the substrate is facilitated by an early commitment to hairpin formation that is imposed by the precleavage action of the hairpin binding module of the ResT active site.Spirochetes of the genus Borrelia are important human pathogens (see (1, 2)) that cause Lyme disease (3, 4) and relapsing fever (5). The Borrelia species possess intriguing genomes in that they are highly segmented with most of their replicons being linear DNAs terminated by covalently closed DNA hairpins, referred to as telomeres (see Ref. 6).The strategy employed by Borrelia burgdorferi to propagate its linear replicons has been described recently (see Refs. 7 and 8). Replication initiates from an internal origin and proceeds bidirectionally (9). Passage of the replication forks through both of the hairpin telomeres would produce an inverted repeat circular dimer replication intermediate. The resulting replicated telomeres are processed by DNA breakage and reunion events (telomere resolution) that liberate the linear daughters from the presumed circular dimer intermediate (10). The enzymatic activity that performs telomere resolution is an essential cellular function provided by ResT, the product of the BBB03 locus of cp26 (11,12). A similar replication strategy has been demonstrated for the N15 bacteriophage, the best characterized example of the bacteriophages that possess linear lysogenic genomes terminated by hairpin telomeres (13-15).Telomere resolution by ResT proceeds by a two-step transesterification involving an active site tyrosine (Tyr 335 ) that proceeds with the same polarity (a DNA-3Јphosphotyrosyl-enzyme intermediate) as that of the type IB topoisomerases and the site-specific recombinase class referred to as tyrosine recombinases (11,16). Nucleophilic attack by the active site tyrosine, on phosphodiester bonds separated by 6 bp on the opposite DNA strands in the replicated telomere, produces a transient covalent 3Ј-phosphotyrosyl-ResT intermediate. Subsequent nucleophilic attack of the phosphotyrosyl linkage b...

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“…ResT recognizes the 25 kb inverted repeats for its function. It has been shown that circular plasmids of B. burgdorferi can replicate as linear derivatives when telomeres are added to the termini (58). Conversely, linear plasmids have also been demonstrated to replicate as circular derivatives in circular vectors (59).…”

Section: Replication Of Linear Plasmids With Closed Endsmentioning

confidence: 99%

Linear plasmids and their replication

Ahsan

Kabir

2013

S.J. Microbiol.

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It is still a common belief that plasmids are circular. However, linear plasmids have been reported to exist more than a decade ago. Two types of linear plasmids are known. One type contains covalently closed ends and are commonly found in Borrelia, the causative agent of tick fever. The other type is characterized by the covalent attachment of proteins at the 5' ends and exists in a number of bacterial genera including Streptomyces, Rhodococcus, Mycobacterium and Planobispora. Recently, a linear plasmid in Salmonella enterica serovar Typhi of the Enterobacteriaceae family have been reported for the first time. This paper reviews various postulated mechanisms of replication of linear plasmids and focuses on the components of the replication machinery of linear plasmids studied to date.

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Telomere resolution in the Lyme disease spirochete

Cited by 95 publications

References 39 publications

Mixing active-site components: A recipe for the unique enzymatic activity of a telomere resolvase

Mixing active-site components: A recipe for the unique enzymatic activity of a telomere resolvase

Uncoupling the Chemical Steps of Telomere Resolution by ResT

Linear plasmids and their replication

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