Duplex DNA and BLM regulate gate opening by the human TopoIIIα-RMI1-RMI2 complex
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Duplex DNA and BLM regulate gate opening by the human TopoIIIα-RMI1-RMI2 complex. / Bakx, Julia A.M.; Biebricher, Andreas S.; King, Graeme A.; Christodoulis, Panagiotis; Sarlós, Kata; Bizard, Anna H.; Hickson, Ian D.; Wuite, Gijs J.L.; Peterman, Erwin J.G.
In: Nature Communications, Vol. 13, No. 1, 584, 2022.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Duplex DNA and BLM regulate gate opening by the human TopoIIIα-RMI1-RMI2 complex
AU - Bakx, Julia A.M.
AU - Biebricher, Andreas S.
AU - King, Graeme A.
AU - Christodoulis, Panagiotis
AU - Sarlós, Kata
AU - Bizard, Anna H.
AU - Hickson, Ian D.
AU - Wuite, Gijs J.L.
AU - Peterman, Erwin J.G.
N1 - Publisher Copyright: © 2022, The Author(s).
PY - 2022
Y1 - 2022
N2 - Topoisomerase IIIα is a type 1A topoisomerase that forms a complex with RMI1 and RMI2 called TRR in human cells. TRR plays an essential role in resolving DNA replication and recombination intermediates, often alongside the helicase BLM. While the TRR catalytic cycle is known to involve a protein-mediated single-stranded (ss)DNA gate, the detailed mechanism is not fully understood. Here, we probe the catalytic steps of TRR using optical tweezers and fluorescence microscopy. We demonstrate that TRR forms an open gate in ssDNA of 8.5 ± 3.8 nm, and directly visualize binding of a second ssDNA or double-stranded (ds)DNA molecule to the open TRR-ssDNA gate, followed by catenation in each case. Strikingly, dsDNA binding increases the gate size (by ~16%), while BLM alters the mechanical flexibility of the gate. These findings reveal an unexpected plasticity of the TRR-ssDNA gate size and suggest that TRR-mediated transfer of dsDNA may be more relevant in vivo than previously believed.
AB - Topoisomerase IIIα is a type 1A topoisomerase that forms a complex with RMI1 and RMI2 called TRR in human cells. TRR plays an essential role in resolving DNA replication and recombination intermediates, often alongside the helicase BLM. While the TRR catalytic cycle is known to involve a protein-mediated single-stranded (ss)DNA gate, the detailed mechanism is not fully understood. Here, we probe the catalytic steps of TRR using optical tweezers and fluorescence microscopy. We demonstrate that TRR forms an open gate in ssDNA of 8.5 ± 3.8 nm, and directly visualize binding of a second ssDNA or double-stranded (ds)DNA molecule to the open TRR-ssDNA gate, followed by catenation in each case. Strikingly, dsDNA binding increases the gate size (by ~16%), while BLM alters the mechanical flexibility of the gate. These findings reveal an unexpected plasticity of the TRR-ssDNA gate size and suggest that TRR-mediated transfer of dsDNA may be more relevant in vivo than previously believed.
U2 - 10.1038/s41467-022-28082-5
DO - 10.1038/s41467-022-28082-5
M3 - Journal article
C2 - 35102151
AN - SCOPUS:85123942278
VL - 13
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
IS - 1
M1 - 584
ER -
ID: 292073231