7ubb

Publication Abstract from PubMed

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, Redbeta from bacteriophage lambda, 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 A structure of a Redbeta 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.

Structure of a RecT/Redbeta family recombinase in complex with a duplex intermediate of DNA annealing.,Caldwell BJ, Norris AS, Karbowski CF, Wiegand AM, Wysocki VH, Bell CE Nat Commun. 2022 Dec 21;13(1):7855. doi: 10.1038/s41467-022-35572-z. PMID:36543802^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.