The bacterial DnaA-trio replication origin element specifies single-stranded DNA initiator binding
Tomas T. Richardson, Omar Harran & Heath Murray
Affiliations Contributions Corresponding author
Received 09 November 2015 Accepted 30 March 2016 Published online 08 June 2016
Structure of DnaA proteins
DNA replication is tightly controlled to ensure accurate inheritance of genetic information. In all organisms, initiator proteins possessing AAA+ (ATPases associated with various cellular activities) domains bind replication origins to license new rounds of DNA synthesis 1. In bacteria the master initiator protein, DnaA, is highly conserved and has two crucial DNA binding activities 2. DnaA monomers recognize the replication origin (oriC) by binding double-stranded DNA sequences (DnaA-boxes); subsequently, DnaA filaments assemble and promote duplex unwinding by engaging and stretching a single DNA strand3, 4, 5. While the specificity for duplex DnaA-boxes by DnaA has been appreciated for over 30 years, the sequence specificity for single-strand DNA binding has remained unknown. Here we identify a new indispensable bacterial replication origin element composed of a repeating trinucleotide motif that we term the DnaA-trio. We show that the function of the DnaA-trio is to stabilize DnaA filaments on a single DNA strand, thus providing essential precision to this binding mechanism. Bioinformatic analysis detects DnaA-trios in replication origins throughout the bacterial kingdom, indicating that this element is part of the core oriC structure. The discovery and characterization of the novel DnaA-trio extends our fundamental understanding of bacterial DNA replication initiation, and because of the conserved structure of AAA+ initiator proteins these findings raise the possibility of specific recognition motifs within replication origins of higher organisms.
Subject terms: Bacterial genetics Origin firing
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PERGUNTA DESTE BLOGGER:
Como melhor explicar a replicação do DNA ser rigidamente controlada a fim de garantir herança exata da informação genética? Mero acaso, fortuita necessidade ou design inteligente???
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PERGUNTA DESTE BLOGGER:
Como melhor explicar a replicação do DNA ser rigidamente controlada a fim de garantir herança exata da informação genética? Mero acaso, fortuita necessidade ou design inteligente???
