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bioRxiv · 10.1101/2020.05.11.089284

DNA ligases of Prochlorococcus marinus: an evolutionary exception to the rules of replication

Hjerde, E.·Maguren, A.·Rzoska-Smith, E.·Kirby, B.·Williamson, A.
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Abstract

DNA ligases, essential enzymes which re-join the backbone of DNA come in two structurally-distinct isoforms, NAD-dependent and ATP-dependent, which differ in cofactor usage. The present view is that all bacteria exclusively use NAD-dependent DNA ligases for DNA replication, while archaea and eukaryotes use ATP-dependent DNA ligases. Some bacteria also possess auxiliary ATP-dependent DNA ligases; however, these are only employed for specialist DNA repair processes. Here we show that in the genomes of high-light strains of the marine cyanobacterium Prochlorococcocus marinus, an ATP-dependent DNA ligase has replaced the NAD-dependent form, overturning the present paradigm of a clear evolutionary split in ligase usage. Genes encoding partial NAD-dependent DNA ligases are found on mobile regions in highlight genomes and lack domains required for catalytic function. This constitutes the first reported example of a bacterium that relies on an ATP-dependent DNA ligase for DNA replication and recommends P. marinus as a model to investigate the evolutionary origins of these essential DNA-processing enzymes.

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Hjerde, E., Maguren, A., Rzoska-Smith, E., Kirby, B., Williamson, A.. 2020-05-13. DNA ligases of Prochlorococcus marinus: an evolutionary exception to the rules of replication. https://doi.org/10.1101/2020.05.11.089284

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