Structural highlights
FunctionREPB_STRAG Is essential for plasmid replication. Nicks the positive strand at the plus origin of replication. Publication Abstract from PubMedDNA replication is essential to all living organisms as it ensures the fidelity of genetic material for the next generation of dividing cells. One of the simplest replication initiation mechanisms is the rolling circle replication. In the streptococcal plasmid pMV158, which confers antibiotic resistance to tetracycline, replication initiation is catalysed by RepB protein. The RepB N-terminal domain or origin binding domain binds to the recognition sequence (bind locus) of the double-strand origin of replication and cleaves one DNA strand at a specific site within the nic locus. Using biochemical and crystallographic analyses, here we show how the origin binding domain recognises and binds to the bind locus using structural elements removed from the active site, namely the recognition alpha helix, and a beta-strand that organises upon binding. A new hexameric structure of full-length RepB that highlights the great flexibility of this protein is presented, which could account for its ability to perform different tasks, namely bind to two distinct loci and cleave one strand of DNA at the plasmid origin. Structures of pMV158 replication initiator RepB with and without DNA reveal a flexible dual-function protein.,Machon C, Ruiz-Maso JA, Amodio J, Boer DR, Bordanaba-Ruiseco L, Bury K, Konieczny I, Del Solar G, Coll M Nucleic Acids Res. 2023 Jan 23:gkac1271. doi: 10.1093/nar/gkac1271. PMID:36688326[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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