Mechanistic basis for relaxation of DNA supercoils by human topoisomerase IIIα-RMI1-RMI2.

ABSTRACT: Topoisomerase enzymes are essential for the regulation of DNA topology. Human topoisomerase IIIα is a Type 1A topoisomerase that exists as a complex with RMI1 and RMI2, known as TRR. The TRR complex can unlink entwined DNA strands and is known to be important for resolving DNA replication and recombination intermediates. It has recently been proposed that TRR can also relax transient negatively supercoiled loops of DNA generated by the translocase PICH and that this activity may help to facilitate the resolution of ultrafine anaphase bridges (UFBs) between segregating sister chromatids. However, the mechanism by which TRR interacts with, and processes, negatively supercoiled DNA is not well understood. Here, we establish a single-molecule strategy to simultaneously measure real-time change

SUBMITTER: Spakman D 

PROVIDER: S-EPMC12849704 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature