A viral scaffolding protein triggers portal ring oligomerization and incorporation during procapsid assembly

Motwani, Tina; Lokareddy, Ravi K.; Dunbar, Carmen A.; Cortines, Juliana R.; Jarrold, Martin F.; Cingolani, Gino; Teschke, Carolyn M.

doi:10.1126/sciadv.1700423

Cited by 39 publications

(57 citation statements)

References 61 publications

(125 reference statements)

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“…Having recently established conditions where we can incorporate portal rings into PLPs assembled in vitro (18), we decided to revisit the Bazinet and King (1988) result through in vitro assembly reactions. First, we tested the effect of portal rings on the kinetics of PLP assembly, as done previously for Φ29 portal protein (10).…”

Section: Resultsmentioning

confidence: 99%

“…A similar result was observed when portal concentration was further raised to 0.2 μM rings (data not shown). We hypothesized that the decrease in the rate of PLP assembly at high concentration of PC portal rings (> 0.1 μM) could be due to interaction of portal protein with SP (18), thereby decreasing the amount of free SP for interaction with CP. Alternatively, too many nuclei could be forming and decreasing the concentration of coat protein available to assemble into PLPs.…”

Section: Resultsmentioning

confidence: 99%

“…Portal rings in the procapsid conformation (PC portal) were purified and assembled as described (18, 19). The portal protein concentration in all experiments is given as the 12-mer ring concentration.…”

Section: Methodsmentioning

confidence: 99%

“…Recently we established an in vitro assembly assay for bacteriophage P22 where portal protein can be co-assembled into procapsid-like particles (PLPs) at a single vertex (18). Furthermore, we showed that scaffolding protein interacts with portal monomers and catalyzes the oligomerization of dodecameric portal rings.…”

Section: Introductionmentioning

confidence: 99%

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The architect of virus assembly: the portal protein complex nucleates procapsid assembly in bacteriophage P22

Motwani

Teschke

2019

Preprint

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24is packaged into a precursor capsid through a 12-mer ring-shaped protein complex 25 called the portal protein, located at a unique 5-fold vertex. In several phages and 26 viruses, including T4, Φ29, and HSV-1, the dodecameric portal protein forms a 27 nucleation complex with scaffolding proteins to initiate procapsid assembly, thereby 28 ensuring incorporation of only one portal complex per capsid. However, for 29 bacteriophage P22, the role of its portal protein in initiation of procapsid assembly is 30 unclear. We recently developed an in vitro P22 assembly assay where portal protein is 31 co-assembled into procapsid-like particles. We also showed that scaffolding protein 32 catalyzes oligomerization of monomeric portal protein into 12-mer rings, and possibly 33 forming a scaffolding-protein nucleation complex that results in one portal complex per 34 P22 procapsid. Here, we present evidence substantiating that P22 portal protein, similar 35 to the other dsDNA viruses, can act as an assembly nucleator. We find that the 36 presence of P22 portal protein is able to increase the rate of particle assembly. 37 Additionally, we show that P22 portal protein proper contributes to proper morphology of 38 the assembled particles. Our results highlight a key function of portal protein as an 39 assembly initiator, a feature likely conserved among these classes of dsDNA viruses. 40 41 Importance 42The existence of a single portal complex is crucial to the formation of mature infectious 43 virions in the tailed dsDNA phages, herpesviruses and adenoviruses, and as such is a 44 3 viable therapeutic target. How only one portal complex is selectively incorporated at a 45 unique vertex is unclear. In many well-characterized dsDNA virus and phages, the 46 portal acts as an assembly nucleator but early work by Bazinet and King (1) indicated 47 that portal protein did not function this way in P22 procapsid assembly, leading to the 48 suggestion that P22 might use a unique mechanism for portal incorporation. Here we 49 show that portal protein does nucleate assembly of P22 procapsid-like particles. 50Addition of portal protein rings to an assembly reaction increases the rate of formation, 51 the yield of particles, and corrects improper morphology. Our data suggest that 52 procapsid assembly may universally initiate with a portal:scaffolding protein complex. 53 54 55 Double stranded DNA (dsDNA) tailed bacteriophages, herpesviruses, some dsDNA 56 archaeal viruses and adenoviruses have a pseudo-icosahedral capsid with a portal 57 protein complex incorporated at a unique five-fold symmetry axis (2-4). The portal 58 complex is a ring of 12 identical subunits constituting an axial channel for the active 59 packaging and ejection of the dsDNA viral genome (1, 5-8). The existence of a single 60 portal complex is crucial to the formation of infectious virions. Evidence from dsDNA 61 bacteriophages such as T4, SPP1, Φ29, and HSV-1 suggests that portal protein 62 complexes play a key role in the nucleation and assembly of proper pro...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The architect of virus assembly: the portal protein complex nucleates procapsid assembly in bacteriophage P22

Motwani

Teschke

2019

Preprint

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“…Rather, structurally conserved domains interact with the viral genome, the major capsid protein, viral scaffold protein, and terminase subunits during packaging into the empty capsid . The assembly of portal monomers likely triggers the co‐polymerization of capsid and scaffolding proteins to form empty procapsids . For herpesviruses, portal is not required for capsid assembly; however, portal‐deficient capsids are not substrates for DNA encapsidation …”

Section: Introductionmentioning

confidence: 99%

Human herpesvirus portal proteins: Structure, function, and antiviral prospects

Kornfeind

Visalli

2018

Reviews in Medical Virology

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Herpesviruses (Herpesvirales) and tailed bacteriophages (Caudovirales) package their dsDNA genomes through an evolutionarily conserved mechanism. Much is known about the biochemistry and structural biology of phage portal proteins and the DNA encapsidation (viral genome cleavage and packaging) process. Although not at the same level of detail, studies on HSV-1, CMV, VZV, and HHV-8 have revealed important information on the function and structure of herpesvirus portal proteins. During dsDNA phage and herpesviral genome replication, concatamers of viral dsDNA are cleaved into single length units by a virus-encoded terminase and packaged into preformed procapsids through a channel located at a single capsid vertex (portal). Oligomeric portals are formed by the interaction of identical portal protein monomers. Comparing portal protein primary aa sequences between phage and herpesviruses reveals little to no sequence similarity. In contrast, the secondary and tertiary structures of known portals are remarkable. In all cases, function is highly conserved in that portals are essential for DNA packaging and also play a role in releasing viral genomic DNA during infection. Preclinical studies have described small molecules that target the HSV-1 and VZV portals and prevent viral replication by inhibiting encapsidation. This review summarizes what is known concerning the structure and function of herpesvirus portal proteins primarily based on their conserved bacteriophage counterparts and the potential to develop novel portal-specific DNA encapsidation inhibitors.

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Advancements in Functional Nanomaterials Inspired by Viral Particles

Sun,

Lian,

Tian

et al. 2024

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Virus‐like particles (VLPs) are nanostructures composed of one or more structural proteins, exhibiting stable and symmetrical structures. Their precise compositions and dimensions provide versatile opportunities for modifications, enhancing their functionality. Consequently, VLP‐based nanomaterials have gained widespread adoption across diverse domains. This review focuses on three key aspects: the mechanisms of viral capsid protein self‐assembly into VLPs, design methods for constructing multifunctional VLPs, and strategies for synthesizing multidimensional nanomaterials using VLPs. It provides a comprehensive overview of the advancements in virus‐inspired functional nanomaterials, encompassing VLP assembly, functionalization, and the synthesis of multidimensional nanomaterials. Additionally, this review explores future directions, opportunities, and challenges in the field of VLP‐based nanomaterials, aiming to shed light on potential advancements and prospects in this exciting area of research.

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A viral scaffolding protein triggers portal ring oligomerization and incorporation during procapsid assembly

Abstract: A novel role for scaffolding protein in portal ring formation.

Cited by 39 publications

References 61 publications

The architect of virus assembly: the portal protein complex nucleates procapsid assembly in bacteriophage P22

The architect of virus assembly: the portal protein complex nucleates procapsid assembly in bacteriophage P22

Human herpesvirus portal proteins: Structure, function, and antiviral prospects

Advancements in Functional Nanomaterials Inspired by Viral Particles

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