8R0F

Capsid structure of Giardiavirus (GLV) HP strain

Summary for 8R0F

• Entry DOI: 10.2210/pdb8r0f/pdb
• EMDB information: 18791
• Descriptor: Capsid protein (1 entity in total)
• Functional Keywords: giardia parasite, dsrna virus, capsid structure, cryo, totiviridae, giardia lambia virus (glv), virus
• Biological source: Giardia lamblia virus
• Total number of polymer chains: 2
• Total formula weight: 206962.64

Authors

Wang, H.,Gianluca, M.,Munke, A.,Hassan, M.M.,Lalle, M.,Okamoto, K. (deposition date: 2023-10-31, release date: 2024-04-03, Last modification date: 2025-07-09)

Primary citation

Wang, H.,Marucci, G.,Munke, A.,Hassan, M.M.,Lalle, M.,Okamoto, K.
High-resolution comparative atomic structures of two Giardiavirus prototypes infecting G. duodenalis parasite.
Plos Pathog., 20:e1012140-e1012140, 2024

PubMed Abstract: The Giardia lamblia virus (GLV) is a non-enveloped icosahedral dsRNA and endosymbiont virus that infects the zoonotic protozoan parasite Giardia duodenalis (syn. G. lamblia, G. intestinalis), which is a pathogen of mammals, including humans. Elucidating the transmission mechanism of GLV is crucial for gaining an in-depth understanding of the virulence of the virus in G. duodenalis. GLV belongs to the family Totiviridae, which infects yeast and protozoa intracellularly; however, it also transmits extracellularly, similar to the phylogenetically, distantly related toti-like viruses that infect multicellular hosts. The GLV capsid structure is extensively involved in the longstanding discussion concerning extracellular transmission in Totiviridae and toti-like viruses. Hence, this study constructed the first high-resolution comparative atomic models of two GLV strains, namely GLV-HP and GLV-CAT, which showed different intracellular localization and virulence phenotypes, using cryogenic electron microscopy single-particle analysis. The atomic models of the GLV capsids presented swapped C-terminal extensions, extra surface loops, and a lack of cap-snatching pockets, similar to those of toti-like viruses. However, their open pores and absence of the extra crown protein resemble those of other yeast and protozoan Totiviridae viruses, demonstrating the essential structures for extracellular cell-to-cell transmission. The structural comparison between GLV-HP and GLV-CAT indicates the first evidence of critical structural motifs for the transmission and virulence of GLV in G. duodenalis.

PubMed: 38598600
DOI: 10.1371/journal.ppat.1012140

Experimental method

ELECTRON MICROSCOPY (2.14 Å)