scholarly journals Dynamic competition for hexon binding between core protein VII and lytic protein VI promotes adenovirus maturation and entry

2019 ◽  
Author(s):  
Mercedes Hernando-Pérez ◽  
Natalia Martín-González ◽  
Marta Pérez-Illana ◽  
Maarit Suomalainen ◽  
Philomena Ostapchuk ◽  
...  
Keyword(s):  
Coat Protein ◽  
Core Protein ◽  
Human Adenovirus ◽  
Dynamic Competition ◽  
Lytic Peptide ◽  
Amino Terminal ◽  
Endosome Escape ◽  
Minor Coat Protein ◽  
Major Core Protein ◽  
Protein Vi

AbstractAdenovirus minor coat protein VI contains a membrane-disrupting peptide which is inactive when VI is bound to hexon trimers. Protein VI must be released during entry to ensure endosome escape. Hexon:VI stoichiometry has been uncertain, and only fragments of VI have been identified in the virion structure. Recent findings suggest an unexpected relationship between VI and the major core protein, VII. According to the high resolution structure of the mature virion, VI and VII may compete for the same binding site in hexon; and non-infectious human adenovirus type 5 particles assembled in the absence of VII (Ad5-VII-) are deficient in proteolytic maturation of protein VI and endosome escape. Here we show that Ad5-VII- particles are trapped in the endosome because they fail to increase VI exposure during entry. This failure was not due to increased particle stability, because capsid disruption happened at lower thermal or mechanical stress in Ad5-VII- compared to wildtype (Ad5-wt) particles. Cryo-EM difference maps indicated that VII can occupy the same binding pocket as VI in all hexon monomers, strongly arguing for binding competition. In the Ad5-VII- map, density corresponding to the immature amino-terminal region of VI indicates that in the absence of VII the lytic peptide is trapped inside the hexon cavity, and clarifies the hexon:VI stoichiometry conundrum. We propose a model where dynamic competition between proteins VI and VII for hexon binding facilitates the complete maturation of VI, and is responsible for releasing the lytic protein from the hexon cavity during entry and stepwise uncoating.Significance StatementCorrect assembly of an adenovirus infectious particle involves the highly regulated interaction of more than ten different proteins as well as the viral genome. Here we examine the interplay between two of these proteins: the major core protein VII, involved in genome condensation, and the multifunctional minor coat protein VI. Protein VI binds to the inner surface of adenovirus hexons (trimers of the major coat protein) and contains a lytic peptide which must be released during entry to ensure endosome rupture. We present data supporting a dynamic competition model between proteins VI and VII for hexon binding during assembly. This competition facilitates the release of the lytic peptide from the hexon cavity and ensures virus escape from the early endosome.

scholarly journals Dynamic competition for hexon binding between core protein VII and lytic protein VI promotes adenovirus maturation and entry

2020 ◽  
Vol 117 (24) ◽  
pp. 13699-13707 ◽  
Author(s):  
Mercedes Hernando-Pérez ◽  
Natalia Martín-González ◽  
Marta Pérez-Illana ◽  
Maarit Suomalainen ◽  
Gabriela N. Condezo ◽  
...  
Keyword(s):  
Core Protein ◽  
Human Adenovirus ◽  
Adenovirus Type ◽  
Binding Pocket ◽  
Dynamic Competition ◽  
Amino Terminal ◽  
Endosome Escape ◽  
Virion Structure ◽  
High Resolution Structure ◽  
Protein Vi

Adenovirus minor coat protein VI contains a membrane-disrupting peptide that is inactive when VI is bound to hexon trimers. Protein VI must be released during entry to ensure endosome escape. Hexon:VI stoichiometry has been uncertain, and only fragments of VI have been identified in the virion structure. Recent findings suggest an unexpected relationship between VI and the major core protein, VII. According to the high-resolution structure of the mature virion, VI and VII may compete for the same binding site in hexon; and noninfectious human adenovirus type 5 particles assembled in the absence of VII (Ad5-VII-) are deficient in proteolytic maturation of protein VI and endosome escape. Here we show that Ad5-VII- particles are trapped in the endosome because they fail to increase VI exposure during entry. This failure was not due to increased particle stability, because capsid disruption happened at lower thermal or mechanical stress in Ad5-VII- compared to wild-type (Ad5-wt) particles. Cryoelectron microscopy difference maps indicated that VII can occupy the same binding pocket as VI in all hexon monomers, strongly arguing for binding competition. In the Ad5-VII- map, density corresponding to the immature amino-terminal region of VI indicates that in the absence of VII the lytic peptide is trapped inside the hexon cavity, and clarifies the hexon:VI stoichiometry conundrum. We propose a model where dynamic competition between proteins VI and VII for hexon binding facilitates the complete maturation of VI, and is responsible for releasing the lytic protein from the hexon cavity during entry and stepwise uncoating.

A bluetongue serogroup-reactive epitope in the amino terminal half of the major core protein VP7 is accessible on the surface of bluetongue virus particles

Virology ◽  
1991 ◽  
Vol 180 (2) ◽  
pp. 687-696 ◽  
Author(s):  
Bryan T. Eaton ◽  
Allan R. Gould ◽  
Alex D. Hyatt ◽  
Barbara E.H. Coupar ◽  
John C. Martyn ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Core Protein ◽  
Virus Particles ◽  
Amino Terminal ◽  
Major Core Protein

scholarly journals Uniqueness of RNA Coliphage Qβ Display System in Directed Evolutionary Biotechnology

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 568
Author(s):  
Godwin W. Nchinda ◽  
Nadia Al-Atoom ◽  
Mamie T. Coats ◽  
Jacqueline M. Cameron ◽  
Alain Bopda Waffo
Keyword(s):  
Life Cycle ◽  
Coat Protein ◽  
Phage Display ◽  
Display System ◽  
Phage Display Technology ◽  
Library Size ◽  
Exterior Surface ◽  
Major Coat Protein ◽  
Display Technology ◽  
Minor Coat Protein

Phage display technology involves the surface genetic engineering of phages to expose desirable proteins or peptides whose gene sequences are packaged within phage genomes, thereby rendering direct linkage between genotype with phenotype feasible. This has resulted in phage display systems becoming invaluable components of directed evolutionary biotechnology. The M13 is a DNA phage display system which dominates this technology and usually involves selected proteins or peptides being displayed through surface engineering of its minor coat proteins. The displayed protein or peptide’s functionality is often highly reduced due to harsh treatment of M13 variants. Recently, we developed a novel phage display system using the coliphage Qβ as a nano-biotechnology platform. The coliphage Qβ is an RNA phage belonging to the family of Leviviridae, a long investigated virus. Qβ phages exist as a quasispecies and possess features making them comparatively more suitable and unique for directed evolutionary biotechnology. As a quasispecies, Qβ benefits from the promiscuity of its RNA dependent RNA polymerase replicase, which lacks proofreading activity, and thereby permits rapid variant generation, mutation, and adaptation. The minor coat protein of Qβ is the readthrough protein, A1. It shares the same initiation codon with the major coat protein and is produced each time the ribosome translates the UGA stop codon of the major coat protein with the of misincorporation of tryptophan. This misincorporation occurs at a low level (1/15). Per convention and definition, A1 is the target for display technology, as this minor coat protein does not play a role in initiating the life cycle of Qβ phage like the pIII of M13. The maturation protein A2 of Qβ initiates the life cycle by binding to the pilus of the F+ host bacteria. The extension of the A1 protein with a foreign peptide probe recognizes and binds to the target freely, while the A2 initiates the infection. This avoids any disturbance of the complex and the necessity for acidic elution and neutralization prior to infection. The combined use of both the A1 and A2 proteins of Qβ in this display system allows for novel bio-panning, in vitro maturation, and evolution. Additionally, methods for large library size construction have been improved with our directed evolutionary phage display system. This novel phage display technology allows 12 copies of a specific desired peptide to be displayed on the exterior surface of Qβ in uniform distribution at the corners of the phage icosahedron. Through the recently optimized subtractive bio-panning strategy, fusion probes containing up to 80 amino acids altogether with linkers, can be displayed for target selection. Thus, combined uniqueness of its genome, structure, and proteins make the Qβ phage a desirable suitable innovation applicable in affinity maturation and directed evolutionary biotechnology. The evolutionary adaptability of the Qβ phage display strategy is still in its infancy. However, it has the potential to evolve functional domains of the desirable proteins, glycoproteins, and lipoproteins, rendering them superior to their natural counterparts.

scholarly journals A Nonviral Peptide Can Replace the Entire N Terminus of Zucchini Yellow Mosaic Potyvirus Coat Protein and Permits Viral Systemic Infection

2001 ◽  
Vol 75 (14) ◽  
pp. 6329-6336 ◽  
Author(s):  
T. Arazi ◽  
Y. M. Shiboleth ◽  
A. Gal-On
Keyword(s):  
Amino Acids ◽  
Coat Protein ◽  
Foot And Mouth Disease ◽  
Systemic Infection ◽  
Deletion Mutants ◽  
Amino Acid Residues ◽  
Amino Terminal ◽  
Immunogenic Epitope ◽  
Mouth Disease Virus ◽  
N Terminus

ABSTRACT Systematic deletion and peptide tagging of the amino-terminal domain (NT, ∼43 amino acids) of an attenuated zucchini yellow mosaic potyvirus (ZYMV-AGII) coat protein (CP) were used to elucidate its role in viral systemic infection. Deletion mutants truncated by 8, 13, and 33 amino acid residues from the CP-NT 5′ end were systemically infectious and produced symptoms similar to those of the AGII virus. Tagging these deletion mutants with either human c-Myc (Myc) or hexahistidine peptides maintained viral infectivity. Similarly, addition of these peptides to the intact AGII CP-NT did not affect viral life cycle. To determine which parts, if any, of the CP-NT are essential for viral systemic infection, a series of Myc-tagged mutants with 8 to 43 amino acids removed from the CP-NT were constructed. All Myc-tagged CP-NT deletion mutants, including those from which virtually all the viral CP-NT had been eliminated, were able to encapsidate and cause systemic infection. Furthermore, chimeric viruses with deletions of up to 33 amino acids from CP-NT produced symptoms indistinguishable from those caused by the parental AGII virus. In contrast to CP-NT Myc fusion, addition of the foot-and-mouth disease virus (FMDV) immunogenic epitope to AGII CP-NT did not permit systemic infection. However, fusion of the Myc peptide to the N terminus of the FMDV peptide restored the capability of the virus to spread systemically. We have demonstrated that all CP-NT fused peptides were exposed on the virion surface, masking natural CP immunogenic determinants. Our findings demonstrate that CP-NT is not essential for ZYMV spread and that it can be replaced by an appropriate foreign peptide while maintaining systemic infectivity.

Mapping of cellular protein-binding sites on the products of early-region 1A of human adenovirus type 5

1988 ◽  
Vol 8 (9) ◽  
pp. 3955-3959 ◽  
Author(s):  
C Egan ◽  
T N Jelsma ◽  
J A Howe ◽  
S T Bayley ◽  
B Ferguson ◽  
...  
Keyword(s):  
Biological Activity ◽  
Binding Sites ◽  
Human Adenovirus ◽  
Adenovirus Type ◽  
Cellular Protein ◽  
Cellular Proteins ◽  
Deletion Mutants ◽  
Protein Binding Sites ◽  
Amino Terminal ◽  
Adenovirus Type 5

The binding sites for the 300-, 107-, and 105-kilodalton cellular proteins which associate with human adenovirus type 5 E1A products were studied with E1A deletion mutants. All appeared to bind to the amino-terminal half of E1A products in regions necessary for oncogenic transformation. These results suggest that these cellular species may be important for the biological activity of E1A products.

scholarly journals The Amino-Terminal Region of Major Capsid Protein P3 Is Essential for Self-Assembly of Single-Shelled Core-Like Particles of Rice Dwarf Virus

2004 ◽  
Vol 78 (6) ◽  
pp. 3145-3148 ◽  
Author(s):  
Kyoji Hagiwara ◽  
Takahiko Higashi ◽  
Naoyuki Miyazaki ◽  
Hisashi Naitow ◽  
R. Holland Cheng ◽  
...  
Keyword(s):  
Self Assembly ◽  
Major Capsid Protein ◽  
Core Protein ◽  
Terminal Region ◽  
Dwarf Virus ◽  
Rice Dwarf Virus ◽  
Amino Terminal ◽  
The Core ◽  
Baculovirus System ◽  
Terminal Amino

ABSTRACT The core protein P3 of Rice dwarf virus constructs asymmetric dimers, one of which is inserted by the amino-terminal region of another P3 protein. The P3 proteins with serial amino-terminal deletions, expressed in a baculovirus system, formed particles with gradually decreasing stability. The capacity for self-assembly disappeared when 52 of the amino-terminal amino acids had been deleted. These results demonstrated that insertion of the amino-terminal arm of one P3 protein into another appears to play an important role in stabilizing the core particles.

Expression of maedi-visna virus major core protein, p25: development of a sensitive p25 antigen detection assay

1992 ◽  
Vol 37 (3) ◽  
pp. 305-320 ◽  
Author(s):  
H.T. Reyburn ◽  
D.J. Roy ◽  
B.A. Blacklaws ◽  
D.R. Sargan ◽  
I. McConnell
Keyword(s):  
Core Protein ◽  
Antigen Detection ◽  
Visna Virus ◽  
Detection Assay ◽  
Maedi Visna Virus ◽  
Major Core Protein
Sign in / Sign up

Export Citation Format

Share Document