Structural Research of Bacteriophage Qβ

Bacteriophage Qβ infects Escherichia coli. It belongs to the family Leviviridae and has a single-stranded RNA genome. The Qβ phage has been extensively studied due to its unique structural features and its role as a model system for understanding viral assembly and RNA replication. In recent years, detailed structural knowledge of the bacteriophage Qβ has led to its use in nanotechnology and biotechnology. Qβ capsids can be used as scaffolds for the presentation of a variety of molecules, including antigens, enzymes, or nanoparticles. These Qβ-based engineered constructs have potential applications in vaccine development, drug delivery systems, and nanoscale biotechnology devices.

Figure 1. The atomic model of bacteriophage Qβ. (Thongchol J, et al., 2023)

Structure of Bacteriophage Qβ

The capsid protein (CP) of single-stranded RNA phage (ssRNA phage) assembles directly around genomic RNA (gRNA) to form an almost icosahedral capsid. The capsid contains the maturation protein (Mat), which binds to the gRNA and interacts with retracted hairs during host infection. Understanding the assembly process of ssRNA phages is essential for their biotechnological applications, including RNA protection and delivery. Researchers successfully modeled the integrated gRNA of ssRNA phage Qβ by collecting gel-filtration-purified Qβ particles with a resolution size of 1.25 Å on cryo-electron microscopy (cryo-EM). The model showed that the 3' untranslated region binds to Mat, and approximately 4127 nucleotides fold domain-by-domain and are connected by long-range RNA-RNA interactions. They also identified 33 manipulator-like RNA stem-loops interacting primarily with asymmetric A/B CP dimers, suggesting a potential pathway for virus-like assembly.

Recent Research Advances in Bacteriophage Qβ

Based on detailed structural information of phage Qβ virus-like particles, researchers have designed novel mutants that, when combined with an essential class of tumor antigens, tumor-associated glycan antigens (TACA), elicit a potent anti-TACA IgG response. In addition to TACA, a phage Qβ-based conjugate vaccine has been shown to induce high levels of IgG antibodies against SARS-CoV-2 viral peptide antigens, demonstrating its versatility in helping to develop a vaccine against COVID-19. Thus, mQβ is a promising platform for next-generation conjugate vaccine vectors, and structure-based rational design is a powerful strategy for developing novel vaccine vectors.

Bacteriophage Qβ has a compact and well-defined structure, making it an ideal system for researching viral RNA replication. Understanding the structural basis of Qβ replication can provide insight into the mechanisms of RNA synthesis and have broader implications for understanding viral invasion strategies. It also helps to understand the assembly of other RNA viruses and may have applications in the design of gene delivery systems. As a leader in viral structural science, Creative Biostructure offers a comprehensive range of virus-like particles (VLPs) to help clients tap into the wide range of application potential that bacteriophage Qβ has.

Creative Biostructure is a preeminent company providing innovative structural analysis services and high-quality VLP products, utilizing cutting-edge structural biology techniques to research the structure and function of biomolecules. Our scientists have extensive experience in cryo-electron microscopy (cryo-EM), which enables us to provide detailed structural analysis services on bacteriophage Qβ.

With our unrivaled expertise in structural biology, we can provide accurate and detailed insights into the structure of viruses. If you would like to learn more about our services or would like to discuss your project with one of our expert scientists, please feel free to contact us. Our distinguished team of scientists is ready to provide the best solution for your project.

References

1. Thongchol J, et al. Recent Advances in Structural Studies of Single-Stranded RNA Bacteriophages. Viruses. 2023. 15(10): 1985.
2. Sungsuwan S, et al. Structure Guided Design of Bacteriophage Qβ Mutants as Next Generation Carriers for Conjugate Vaccines. ACS Chem Biol. 2022. 17(11): 3047-3058.
3. Chang JY, et al. Structural Assembly of Qβ Virion and Its Diverse Forms of Virus-like Particles. Viruses. 2022. 14(2): 225.