TopA, the Sulfolobus solfataricus topoisomerase III, is a decatenase

TY - JOUR

T1 - TopA, the Sulfolobus solfataricus topoisomerase III, is a decatenase

AU - Bizard, Anna H.

AU - Yang, Xi

AU - Débat, Hélène

AU - Fogg, Jonathan M.

AU - Zechiedrich, Lynn

AU - Strick, Terence R.

AU - Garnier, Florence

AU - Nadal, Marc

PY - 2018

Y1 - 2018

N2 - DNA topoisomerases are essential enzymes involved in all the DNA processes and among them, type IA topoisomerases emerged as a key actor in the maintenance of genome stability. The hyperthermophilic archaeon, Sulfolobus solfataricus, contains three topoisomerases IA including one classical named TopA. SsoTopA is very efficient at unlinking DNA catenanes, grouping SsoTopA into the topoisomerase III family. SsoTopA is active over a wide range of temperatures and at temperatures of up to 85 °C it produces highly unwound DNA. At higher temperatures, SsoTopA unlinks the two DNA strands. Thus depending on the temperature, SsoTopA is able to either prevent or favor DNA melting. While canonical topoisomerases III require a single-stranded DNA region or a nick in one of the circles to decatenate them, we show for the first time that a type I topois merase, SsoTopA, is able to efficiently unlink covalently closed catenanes, with no additional partners. By using single molecule experiments we demonstrate that SsoTopA requires the presence of a short single-stranded DNA region to be efficient. The unexpected decatenation property of SsoTopA probably comes from its high ability to capture this unwound region. This points out a possible role of TopA in S. solfataricus as a decatenase in Sulfolobus.

AB - DNA topoisomerases are essential enzymes involved in all the DNA processes and among them, type IA topoisomerases emerged as a key actor in the maintenance of genome stability. The hyperthermophilic archaeon, Sulfolobus solfataricus, contains three topoisomerases IA including one classical named TopA. SsoTopA is very efficient at unlinking DNA catenanes, grouping SsoTopA into the topoisomerase III family. SsoTopA is active over a wide range of temperatures and at temperatures of up to 85 °C it produces highly unwound DNA. At higher temperatures, SsoTopA unlinks the two DNA strands. Thus depending on the temperature, SsoTopA is able to either prevent or favor DNA melting. While canonical topoisomerases III require a single-stranded DNA region or a nick in one of the circles to decatenate them, we show for the first time that a type I topois merase, SsoTopA, is able to efficiently unlink covalently closed catenanes, with no additional partners. By using single molecule experiments we demonstrate that SsoTopA requires the presence of a short single-stranded DNA region to be efficient. The unexpected decatenation property of SsoTopA probably comes from its high ability to capture this unwound region. This points out a possible role of TopA in S. solfataricus as a decatenase in Sulfolobus.

U2 - 10.1093/nar/gkx1247

DO - 10.1093/nar/gkx1247

M3 - Journal article

C2 - 29253195

AN - SCOPUS:85044636930

SN - 0305-1048

VL - 46

SP - 861

EP - 872

JO - Nucleic Acids Research

JF - Nucleic Acids Research

IS - 2

ER -