Structural basis of DNA packaging by a ring-type ATPase from an archetypal viral system

Fung, H. K. H.; Grimes, S.; Huet, A.; Duda, R. L.; Chechik, M.; Gault, J.; Robinson, C. V.; Hendrix, R. W.; Jardine, P. J.; Conway, J. F.; Baumann, C. G.; Antson, A. A.

doi:10.1101/2022.05.10.491410

bioRxiv · 10.1101/2022.05.10.491410

Structural basis of DNA packaging by a ring-type ATPase from an archetypal viral system

Fung, H. K. H.·Grimes, S.·Huet, A.·Duda, R. L.·Chechik, M.·Gault, J.·Robinson, C. V.·Hendrix, R. W.·Jardine, P. J.·Conway, J. F.·Baumann, C. G.·Antson, A. A.

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Abstract

Many essential cellular processes rely on substrate rotation or translocation by a multi-subunit, ring-type NTPase. A large number of double-stranded DNA viruses, including tailed bacteriophages and herpes viruses, use a homomeric ring ATPase to processively translocate viral genomic DNA into procapsids during assembly. Our current understanding of viral DNA packaging comes from three archetypal bacteriophage systems: cos, pac and phi29. Detailed mechanistic understanding exists for pac and phi29, but not for cos. Here we reconstituted in vitro a cos packaging system based on bacteriophage HK97 and provided a detailed biochemical and structural description. We used a photobleaching-based, single-molecule assay to determine the stoichiometry of the DNA-translocating ATPase large terminase. Crystal structures of the large terminase and DNA-recruiting small terminase, a first for both this phage and a cos system, reveal unexpected mechanistic similarities between cos and pac systems. At the same time, mutational and biochemical analyses indicate a new regulatory mechanism for ATPase multimerization and coordination in the HK97 system. This work therefore establishes a framework for studying the evolutionary relationships between ATP-dependent DNA translocation machineries in double-stranded DNA viruses.

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Fung, H. K. H., Grimes, S., Huet, A., Duda, R. L., Chechik, M., Gault, J., Robinson, C. V., Hendrix, R. W., Jardine, P. J., Conway, J. F., Baumann, C. G., Antson, A. A.. 2022-05-10. Structural basis of DNA packaging by a ring-type ATPase from an archetypal viral system. https://doi.org/10.1101/2022.05.10.491410

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