Structural highlights
Publication Abstract from PubMedThe Redbeta protein of the bacteriophage lambda 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 Redbeta, 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 A. 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 Redbeta 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 Redbeta, a defining member of the Redbeta/RecT protein family. Redbeta(177) annealase structure reveals details of oligomerization and lambda Red-mediated homologous DNA recombination.,Newing TP, Brewster JL, Fitschen LJ, Bouwer JC, Johnston NP, Yu H, Tolun G Nat Commun. 2022 Sep 26;13(1):5649. doi: 10.1038/s41467-022-33090-6. PMID:36163171[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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