Research Projects

The RecQ family of DNA helicases is crucial for genome stability and can unwind complex DNA substrates like forked duplexes, D-loops, 3- or 4-way junctions, and G-quadruplex DNA. Human RECQ1, the smallest and first RecQ helicase, has been identified but the molecular mechanisms for specific substrate recognition, DNA binding, and strand annealing activity remain poorly explored. RecQ helicases like E.coli RecQ, BLM, and human RECQ1 differ significantly in their substrate selectivity, with the structural basis for substrate selectivity still poorly understood. From crystal structure data and biochemical evidence, it was proposed that the Winged helix (WH) domain of human RECQ1 is directly involved in strand annealing activity. Recent studies from our laboratory also support this hypothesis, with a significant difference in the orientations of human RECQ1 and E.coli RecQ. To explore the role of WH domain conformation, we propose using a functional mutant of human RECQ1 developed in our laboratory. This will help us decipher the conformational requirement of the Winged helix domain for DNA binding and recognition, as well as gain insight into the conformational change in the WH domain that favors DNA binding and strand annealing activities. Additionally, we will construct chimeric RecQ helicases fusing domains from human RECQ1 and E.coli RecQ, providing further insight into the WH domain conformation crucial for substrate recognition.