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Redβ177 annealase structure reveals details of oligomerization and λ Red-mediated homologous DNA recombination.

Journal Article


Abstract


  • The Redβ protein of the bacteriophage λ red recombination system is a model annealase which catalyzes single-strand annealing homologous DNA recombination. Here we present the structure of a helical oligomeric annealing intermediate of Redβ, consisting of N-terminal residues 1-177 bound to two complementary 27mer oligonucleotides, determined via cryogenic electron microscopy (cryo-EM) to a final resolution of 3.3 Å. The structure reveals a continuous binding groove which positions and stabilizes complementary DNA strands in a planar orientation to facilitate base pairing via a network of hydrogen bonding. Definition of the inter-subunit interface provides a structural basis for the propensity of Redβ to oligomerize into functionally significant long helical filaments, a trait shared by most annealases. Our cryo-EM structure and molecular dynamics simulations suggest that residues 133-138 form a flexible loop which modulates access to the binding groove. More than half a century after its discovery, this combination of structural and computational observations has allowed us to propose molecular mechanisms for the actions of the model annealase Redβ, a defining member of the Redβ/RecT protein family.

Publication Date


  • 2022

Citation


  • Newing, T. P., Brewster, J. L., Fitschen, L. J., Bouwer, J. C., Johnston, N. P., Yu, H., & Tolun, G. (2022). Redβ177 annealase structure reveals details of oligomerization and λ Red-mediated homologous DNA recombination.. Nature communications, 13(1), 5649. doi:10.1038/s41467-022-33090-6

Web Of Science Accession Number


Start Page


  • 5649

Volume


  • 13

Issue


  • 1

Abstract


  • The Redβ protein of the bacteriophage λ red recombination system is a model annealase which catalyzes single-strand annealing homologous DNA recombination. Here we present the structure of a helical oligomeric annealing intermediate of Redβ, consisting of N-terminal residues 1-177 bound to two complementary 27mer oligonucleotides, determined via cryogenic electron microscopy (cryo-EM) to a final resolution of 3.3 Å. The structure reveals a continuous binding groove which positions and stabilizes complementary DNA strands in a planar orientation to facilitate base pairing via a network of hydrogen bonding. Definition of the inter-subunit interface provides a structural basis for the propensity of Redβ to oligomerize into functionally significant long helical filaments, a trait shared by most annealases. Our cryo-EM structure and molecular dynamics simulations suggest that residues 133-138 form a flexible loop which modulates access to the binding groove. More than half a century after its discovery, this combination of structural and computational observations has allowed us to propose molecular mechanisms for the actions of the model annealase Redβ, a defining member of the Redβ/RecT protein family.

Publication Date


  • 2022

Citation


  • Newing, T. P., Brewster, J. L., Fitschen, L. J., Bouwer, J. C., Johnston, N. P., Yu, H., & Tolun, G. (2022). Redβ177 annealase structure reveals details of oligomerization and λ Red-mediated homologous DNA recombination.. Nature communications, 13(1), 5649. doi:10.1038/s41467-022-33090-6

Web Of Science Accession Number


Start Page


  • 5649

Volume


  • 13

Issue


  • 1