Document Type
Article
Publication Date
2013
Digital Object Identifier (DOI)
https://doi.org/10.1093/nar/gkt817
Abstract
The RecQ-like DNA helicase family is essential for the maintenance of genome stability in all organisms. Sgs1, a member of this family in Saccharomyces cerevisiae, regulates early and late steps of double-strand break repair by homologous recombination. Using nuclear magnetic resonance spectroscopy, we show that the N-terminal 125 residues of Sgs1 are disordered and contain a transient α-helix that extends from residue 25 to 38. Based on the residue-specific knowledge of transient secondary structure, we designed proline mutations to disrupt this α-helix and observed hypersensitivity to DNA damaging agents and increased frequency of genome rearrangements. In vitro binding assays show that the defects of the proline mutants are the result of impaired binding of Top3 and Rmi1 to Sgs1. Extending mutagenesis N-terminally revealed a second functionally critical region that spans residues 9–17. Depending on the position of the proline substitution in the helix functional impairment of Sgs1 function varied, gradually increasing from the C- to the N-terminus. The multiscale approach we used to interrogate structure/function relationships in the long disordered N-terminal segment of Sgs1 allowed us to precisely define a functionally critical region and should be generally applicable to other disordered proteins.
Rights Information
This work is licensed under a Creative Commons Attribution 3.0 License.
Was this content written or created while at USF?
Yes
Citation / Publisher Attribution
Nucleic Acids Research, v. 41, issue 22, p. 10215-10227
Scholar Commons Citation
Kennedy, Jessica A.; Daughdrill, Gary W.; and Schmidt, Kristina H., "A Transient α-helical Molecular Recognition Element in the Disordered N-terminus of the Sgs1 Helicase is Critical for Chromosome Stability and Binding of Top3/Rmi1" (2013). Molecular Biosciences Faculty Publications. 78.
https://digitalcommons.usf.edu/bcm_facpub/78
