RQC helical hairpin in Bloom's syndrome helicase regulates DNA unwinding by dynamically intercepting nascent nucleotides.

ABSTRACT: The RecQ family of helicases are important for maintenance of genomic integrity. Although functions of constructive subdomains of this family of helicases have been extensively studied, the helical hairpin (HH) in the RecQ-C-terminal domain (RQC) has been underappreciated and remains poorly understood. Here by using single-molecule fluorescence resonance energy transfer, we found that HH in the human BLM transiently intercepts different numbers of nucleotides when it is unwinding a double-stranded DNA. Single-site mutations in HH that disrupt hydrogen bonds and/or salt bridges between DNA and HH change the DNA binding conformations and the unwinding features significantly. Our results, together with recent clinical tests that correlate single-site mutations in HH of human BLM with the phen

SUBMITTER: Ma J 

PROVIDER: S-EPMC8718986 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature