Structural diversity and conservation among CRESS-DNA bacilladnaviruses revealed through cryo-EM and computational modelling
Gebhard, L. Johanna ; Tomaru, Yuji ; Okamoto, Kenta and Munke, Anna LU
(2025)
In Virology Journal
22.
- Abstract
- Viruses that infect single-celled algae strongly regulate microalgae
growth and community composition through cell lysis, enable nutrient
recycling in marine ecosystems, and offer valuable insights into early
stages of viral evolution. One major group, the Bacilladnaviridae family of single-stranded DNA viruses, infects diatoms in marine environments. Here, we present the capsid structure of Chaetoceros lorenzianus DNA virus (ClorDNAV, Protobacilladnavirus chaelor) determined at 2.2 Å resolution, thereby expanding the known structural diversity within the Cressdnaviricota
phylum. The ClorDNAV capsid protein (CP) contains a conserved
jelly-roll fold and a surface-exposed projection... (More) - Viruses that infect single-celled algae strongly regulate microalgae
growth and community composition through cell lysis, enable nutrient
recycling in marine ecosystems, and offer valuable insights into early
stages of viral evolution. One major group, the Bacilladnaviridae family of single-stranded DNA viruses, infects diatoms in marine environments. Here, we present the capsid structure of Chaetoceros lorenzianus DNA virus (ClorDNAV, Protobacilladnavirus chaelor) determined at 2.2 Å resolution, thereby expanding the known structural diversity within the Cressdnaviricota
phylum. The ClorDNAV capsid protein (CP) contains a conserved
jelly-roll fold and a surface-exposed projection domain, with both N-
and C-termini oriented toward the capsid interior. A low-resolution
reconstruction of the genome revealed a spooled arrangement of the outer
DNA layer, similar to that observed in Chaetoceros tenuissimus
DNA virus type II (CtenDNAV-II). Structural comparison with CtenDNAV-II
revealed five key CP differences: the absence of surface-exposed
C-terminal tails in ClorDNAV, the presence of a helical domain,
differences in the projection domain conformation, variation in the
number of β-strands in the jelly-roll fold, and the lack of
ion-attributed densities at subunit interfaces. Together with the genome
reconstruction, these findings underscore the importance of
experimentally determined structures for understanding viral
architecture and evolution. To complement these results, we analyzed
AlphaFold3-predicted CPs from all classified Bacilladnaviridae
genera. These models confirmed the conservation of the jelly-roll fold
across the family while revealing variability in the surface-exposed and
terminal regions, likely reflecting host-specific adaptations and
genome packaging strategies. Together, the experimental and predicted
structures provide a comprehensive view of structural conservation and
divergence in Bacilladnaviridae. Furthermore, the results provide additional structural evidence for the evolution of ssDNA Bacilladnaviridae from a noda-like ssRNA virus ancestor and suggest a shared genome organization resembling that of double-stranded viruses. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/e8d755b3-7d9f-4418-b085-f7c03f36b53c
- author
- Gebhard, L. Johanna
; Tomaru, Yuji
; Okamoto, Kenta
and Munke, Anna
LU
- organization
- publishing date
- 2025-12-01
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Virology Journal
- volume
- 22
- article number
- 391
- pages
- 10 pages
- publisher
- BioMed Central (BMC)
- external identifiers
-
- scopus:105023452887
- ISSN
- 1743-422X
- DOI
- 10.1186/s12985-025-03019-8
- language
- English
- LU publication?
- yes
- id
- e8d755b3-7d9f-4418-b085-f7c03f36b53c
- alternative location
- https://virologyj.biomedcentral.com/articles/10.1186/s12985-025-03019-8
- date added to LUP
- 2025-12-01 17:37:47
- date last changed
- 2025-12-15 04:00:54
@article{e8d755b3-7d9f-4418-b085-f7c03f36b53c,
abstract = {{Viruses that infect single-celled algae strongly regulate microalgae <br>
growth and community composition through cell lysis, enable nutrient <br>
recycling in marine ecosystems, and offer valuable insights into early <br>
stages of viral evolution. One major group, the <i>Bacilladnaviridae</i> family of single-stranded DNA viruses, infects diatoms in marine environments. Here, we present the capsid structure of <i>Chaetoceros lorenzianus</i> DNA virus (ClorDNAV, <i>Protobacilladnavirus chaelor</i>) determined at 2.2 Å resolution, thereby expanding the known structural diversity within the <i>Cressdnaviricota</i><br>
phylum. The ClorDNAV capsid protein (CP) contains a conserved <br>
jelly-roll fold and a surface-exposed projection domain, with both N- <br>
and C-termini oriented toward the capsid interior. A low-resolution <br>
reconstruction of the genome revealed a spooled arrangement of the outer<br>
DNA layer, similar to that observed in <i>Chaetoceros tenuissimus</i> <br>
DNA virus type II (CtenDNAV-II). Structural comparison with CtenDNAV-II <br>
revealed five key CP differences: the absence of surface-exposed <br>
C-terminal tails in ClorDNAV, the presence of a helical domain, <br>
differences in the projection domain conformation, variation in the <br>
number of β-strands in the jelly-roll fold, and the lack of <br>
ion-attributed densities at subunit interfaces. Together with the genome<br>
reconstruction, these findings underscore the importance of <br>
experimentally determined structures for understanding viral <br>
architecture and evolution. To complement these results, we analyzed <br>
AlphaFold3-predicted CPs from all classified <i>Bacilladnaviridae</i> <br>
genera. These models confirmed the conservation of the jelly-roll fold <br>
across the family while revealing variability in the surface-exposed and<br>
terminal regions, likely reflecting host-specific adaptations and <br>
genome packaging strategies. Together, the experimental and predicted <br>
structures provide a comprehensive view of structural conservation and <br>
divergence in <i>Bacilladnaviridae</i>. Furthermore, the results provide additional structural evidence for the evolution of ssDNA <i>Bacilladnaviridae</i> from a noda-like ssRNA virus ancestor and suggest a shared genome organization resembling that of double-stranded viruses.}},
author = {{Gebhard, L. Johanna and Tomaru, Yuji and Okamoto, Kenta and Munke, Anna}},
issn = {{1743-422X}},
language = {{eng}},
month = {{12}},
publisher = {{BioMed Central (BMC)}},
series = {{Virology Journal}},
title = {{Structural diversity and conservation among CRESS-DNA bacilladnaviruses revealed through cryo-EM and computational modelling}},
url = {{http://dx.doi.org/10.1186/s12985-025-03019-8}},
doi = {{10.1186/s12985-025-03019-8}},
volume = {{22}},
year = {{2025}},
}