Premium
Unexpected twist: harnessing the energy in positive supercoils to control telomere resolution
Author(s) -
Bankhead Troy,
Kobryn Kerri,
Chaconas George
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05423.x
Subject(s) - dna supercoil , biology , telomere , dna , tn3 transposon , biophysics , microbiology and biotechnology , genetics , dna replication , mutant , gene , transposable element
Summary Negative DNA supercoiling is an important conformational property of bacterial DNA that plays a significant role in a wide variety of DNA transactions. In contrast, positive DNA supercoiling is a by‐product of cellular processes that involve helical unwinding or movement of DNA by a fixed translocase, and has generally been considered a necessary evil requiring removal. We now report the first evidence suggesting a physiological role for positive supercoiling; this occurs in telomere resolution in the related Lyme disease and relapsing fever Borrelia spirochetes. Telomere resolution is the process whereby covalently closed hairpin telomeres are generated from replicative intermediates by the telomere resolvase, ResT. We observe a 20‐fold and greater stimulation of the reaction by positive supercoiling, which facilitates formation of a previously unobserved reaction intermediate. Our data suggest the possibility that the free energy of positive supercoiling, a resource with no previously described cellular function, may be harnessed and utilized as a regulator of post‐replication events.