Related Experiment Video
Updated: Jun 16, 2026
08:40
Production of Pseudotyped Particles to Study Highly Pathogenic Coronaviruses in a Biosafety Level 2 Setting
Published on: March 1, 2019
Structure and function of a genetically engineered mimic of a nonenveloped virus entry intermediate
Manidipa Banerjee1, Jeffrey A Speir, Maggie H Kwan
1Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Journal of Virology
|February 19, 2010
Summary
Calcium ions are crucial for Flock House virus (FHV) capsid stability and infectivity. Blocking calcium binding exposes a viral peptide, impacting host cell entry and membrane disruption.
Area of Science:
- Virology
- Structural Biology
- Biochemistry
Background:
- Divalent metal ions are integral to many icosahedral virus capsid structures.
- Flock House virus (FHV) serves as a model to study metal ion effects on virus biology.
Purpose of the Study:
- To investigate the role of calcium ions in FHV capsid stability and infectivity.
- To understand how metal ion binding influences virus-host interactions and entry mechanisms.
Main Methods:
- Site-directed mutagenesis of FHV calcium-binding sites.
- Analysis of capsid stability and infectivity.
- Conformational analysis of the gamma peptide under varying pH conditions.
Main Results:
- Mutations at calcium-binding sites destabilized the FHV capsid and significantly reduced infectivity.
- Capsid architecture remained unchanged, but gamma peptide exposure increased at neutral pH.
- Calcium binding is essential for pH-dependent control of gamma peptide exposure and membrane disruption.
Conclusions:
- Calcium ions are vital for maintaining FHV structural integrity and regulating viral peptide exposure.
- FHV calcium-binding mutants mimic an early endosomal entry intermediate.
- This reveals a novel mechanism for metal ion requirement in virus entry and infectivity.
More Related Videos
Related Concept Videos
00:56Viral Structure
Viruses are extraordinarily diverse in shape and size, but they all have several structural features in common. All viruses have a core that contains a DNA- or RNA-based genome. The core is surrounded by a protective coat of proteins called the capsid. The capsid is composed of subunits called capsomeres. The capsid and genome-containing core are together known as the nucleocapsid.
01:28Introduction to Virus
Viruses are unique biological entities that blur the boundary between living and non-living systems. Although they lack cellular structure and metabolic processes, they can exhibit characteristics of life when infecting a host. Their defining feature is a nucleic acid core, composed of either DNA or RNA, encapsulated within a protein coat called a capsid. This simple structure allows them to invade host cells and use their machinery for replication efficiently.Viral Structure and...
01:19Inhibitors of Virion Maturation and Assembly
As part of their replication cycle, certain viruses synthesize long precursor proteins called polyproteins within infected host cells. In human immunodeficiency virus (HIV), two major polyproteins are produced: Gag and Gag-Pol. The Gag polyprotein supplies the structural components of the virus, while Gag-Pol includes essential viral enzymes such as reverse transcriptase, integrase, and protease. After synthesis, these polyproteins move to the host cell membrane, where they assemble into an...
01:25Inhibitors Of Virion Release
Viral replication and dissemination rely on efficient mechanisms for host cell entry, genome replication, assembly, and release. Influenza viruses, such as types A and B, are negative-sense single-stranded RNA viruses with a segmented genome, that depend on two critical surface glycoproteins to carry out these processes: hemagglutinin (HA) and neuraminidase (NA). HA initiates infection by binding to sialic acid residues on the surface of host epithelial cells, facilitating receptor-mediated...
01:10Retrovirus Life Cycles
Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...
01:38Intralumenal Vesicles and Multivesicular Bodies
Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...