The G-quadruplex (G4) resolvase DHX36 efficiently and specifically disrupts DNA G4s via a translocation-based helicase mechanism.

ABSTRACT: Single-stranded DNA (ssDNA) and RNA regions that include at least four closely spaced runs of three or more consecutive guanosines strongly tend to fold into stable G-quadruplexes (G4s). G4s play key roles as DNA regulatory sites and as kinetic traps that can inhibit biological processes, but how G4s are regulated in cells remains largely unknown. Here, we developed a kinetic framework for G4 disruption by DEAH-box helicase 36 (DHX36), the dominant G4 resolvase in human cells. Using tetramolecular DNA and RNA G4s with four to six G-quartets, we found that DHX36-mediated disruption is highly efficient, with rates that depend on G4 length under saturating conditions (k_cat) but not under subsaturating conditions (k_cat/K_m ). These results s

SUBMITTER: Yangyuoru PM 

PROVIDER: S-EPMC5808756 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature