RT Journal Article
SR Electronic
T1 Human HELB is a processive motor protein which catalyses RPA clearance from single-stranded DNA
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.05.27.445972
DO 10.1101/2021.05.27.445972
A1 S Hormeno
A1 OJ Wilkinson
A1 C Aicart-Ramos
A1 S Kuppa
A1 E Antony
A1 MS Dillingham
A1 F Moreno-Herrero
YR 2021
UL http://biorxiv.org/content/early/2021/05/27/2021.05.27.445972.abstract
AB Human HELB is a poorly-characterised helicase suggested to play both positive and negative regulatory roles in DNA replication and recombination. In this work, we used bulk and single molecule approaches to characterise the biochemical activities of HELB protein with a particular focus on its interactions with RPA and RPA-ssDNA filaments. HELB is a monomeric protein which binds tightly to ssDNA with a site size of ∼20 nucleotides. It couples ATP hydrolysis to translocation along ssDNA in the 5′-to-3′ direction accompanied by the formation of DNA loops and with an efficiency of 1 ATP per base. HELB also displays classical helicase activity but this is very weak in the absence of an assisting force. HELB binds specifically to human RPA which enhances its ATPase and ssDNA translocase activities but inhibits DNA unwinding. Direct observation of HELB on RPA nucleoprotein filaments shows that translocating HELB concomitantly clears RPA from single-stranded DNA.Competing Interest StatementThe authors have declared no competing interest.