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Caldwell BJ, Norris AS, Karbowski CF, Wiegand AM, Wysocki VH, Bell CE. Structure of a RecT/Redβ family recombinase in complex with a duplex intermediate of DNA annealing. Nat Commun 2022; 13:7855. [PMID: 36543802 PMCID: PMC9772228 DOI: 10.1038/s41467-022-35572-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Some bacteriophage encode a recombinase that catalyzes single-stranded DNA annealing (SSA). These proteins are apparently related to RAD52, the primary human SSA protein. The best studied protein, Redβ from bacteriophage λ, binds weakly to ssDNA, not at all to dsDNA, but tightly to a duplex intermediate of annealing formed when two complementary DNA strands are added to the protein sequentially. We used single particle cryo-electron microscopy (cryo-EM) to determine a 3.4 Å structure of a Redβ homolog from a prophage of Listeria innocua in complex with two complementary 83mer oligonucleotides. The structure reveals a helical protein filament bound to a DNA duplex that is highly extended and unwound. Native mass spectrometry confirms that the complex seen by cryo-EM is the predominant species in solution. The protein shares a common core fold with RAD52 and a similar mode of ssDNA-binding. These data provide insights into the mechanism of protein-catalyzed SSA.
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Affiliation(s)
- Brian J Caldwell
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Andrew S Norris
- Department of Chemistry and Biochemistry and Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Caroline F Karbowski
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Alyssa M Wiegand
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Vicki H Wysocki
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA
- Department of Chemistry and Biochemistry and Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Charles E Bell
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, 43210, USA.
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA.
- Department of Chemistry and Biochemistry and Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH, 43210, USA.
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