Architecture of the herpesvirus genome-packaging complex and implications for DNA translocation

Abstract

Genome packaging is a fundamental process in a viral life cycle and a prime target of antiviral drugs. Herpesviruses use an ATP-driven packaging motor/terminase complex to translocate and cleave concatemeric dsDNA into procapsids but its molecular architecture and mechanism are unknown. We report atomic structures of a herpesvirus hexameric terminase complex in both the apo and ADP•BeF3-bound states. Each subunit of the hexameric ring comprises three components-the ATPase/terminase pUL15 and two regulator/fixer proteins, pUL28 and pUL33-unlike bacteriophage terminases. Distal to the nuclease domains, six ATPase domains form a central channel with conserved basicpatches conducive to DNA binding and transacting arginine fingers are essential to ATP hydrolysis and sequential DNA translocation. Rearrangement of the nuclease domains mediated by regulatory domains converts DNA translocation mode to cleavage mode. Our structures favor a sequential revolution model for DNA translocation and suggest mechanisms for concerted domain rearrangements leading to DNA cleavage. KEYWORDS dsDNA virus, genome packaging, viral maturation, terminase complex, drug target Yunxiang Yang and Pan Yang contributed equally to this work.

Structures of Echovirus 30 in complex with its receptors inform a rational prediction for enterovirus receptor usage

“…Generally, the standard verification of a bona fide viral receptor involves a number of assays, such as that expression of this receptor enables normally unsusceptible cell lines to support viral propagation; loss of expression of this receptor or its binding partner (e.g., antibodies) renders cells resistant to viral infection; soluble receptor could directly bind viral particles and neutralizes infection, but these assays are timeconsuming. By contrast, the recent 'resolution revolution' in cryo-EM has accelerated the process for determining high-resolution structures of a wide array of previously intractable biological systems [52][53][54][55][56][57][58] . In this study, we provided models for E30 in complex with its receptors CD55 and FcRn and systematically analyzed available human EVs-receptor interactions, which pinpointed key structure-receptor usage correlates.…”

High resolution structure of hexameric herpesvirus DNA-packaging motor elucidates revolving mechanism and ends 20-year fervent debate

“…However, the diameter of many connector portal channels of procapsids/assembly intermediates in dsDNA bacteriophages are larger than the diameter of the dsDNA (Schwartz et al, 2013;Zhao et al, 2013;Guo et al, 2014Guo et al, , 2019. The channel of the herpesvirus motor as reported here is about 50% larger than that of dsDNA (Wang et al, 2020; Yang et al, 2020), indicative of an impossibility for nutand-bolt rotation. This herpesvirus hexameric motor ring is formed by six subunits of heterotrimer that contain pUL15, pUL28 and pUL33.…”

“…In this issue of the Protein & Cell Journal, a research team (from Institute of Biophysics, Chinese Academy of Sciences) led by professors Xiangxi Wang and Zihe Rao report the high-resolution structural and physical properties of the ATPdriven DNA packaging motor of the double-stranded (ds) herpesvirus (Yang et al 2020). The structures of the portal vertex, the channel hub of the DNA packaging motor were also investigated, revealing essential protein-protein interactions in the assembly and maturation of herpesvirus procapsid (Chen et al 2020;Wang et al 2020).…”

Structural changes of a bacteriophage upon DNA packaging and maturation

“…S9B). The clip tilts toward the portal axis, which probably triggers the disassociation of the terminase complex (Yang et al, 2020), followed by the assembly of the tail proteins. It is noteworthy that If the portal does not move downward and expose its clip domain out of the capsid shell, the tail is not able to assemble on the portal due to steric restriction.…”

“…At the beginning of phage infection, the tail is responsible for receptor recognition, and the portal and tail act as a tunnel for DNA delivery into the host cytoplasm (Johnson and Chiu, 2007). These mechanisms of DNA packaging and ejection may also be conserved in many other DNA viruses, including herpesvirus (Wang et al, 2020;Yang et al, 2020).…”