Related Experiment Video
Updated: Dec 18, 2025
09:08
Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus
Published on: July 27, 2021
4.1K
The Dynamic Life of Virus Capsids
Michael B Sherman1, Hong Q Smith1, Thomas J Smith1
1Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, 301 University Boulevard, Route 0645, Galveston, TX 77555, USA.
Viruses
|June 11, 2020
Summary
Viruses are not passive "tin cans." Flexible protein capsids of human rhinoviruses and mouse noroviruses (MNV) actively respond to environmental cues, enabling genome release and host cell infection.
Area of Science:
- Virology
- Structural Biology
- Molecular Biology
Background:
- Traditionally, protein-shelled viruses were viewed as inert carriers of genetic material.
- Emerging evidence reveals viruses like rhinoviruses and caliciviruses possess dynamic capsids that actively respond to environmental signals.
Purpose of the Study:
- To investigate the dynamic nature of viral protein capsids.
- To elucidate the mechanisms by which viruses like human rhinovirus and mouse norovirus (MNV) interact with host cells and evade the immune system.
Main Methods:
- Analysis of viral capsid structure and conformational changes.
- Investigating the role of environmental cues (e.g., receptor binding, bile salts) in viral activation.
Main Results:
- Human rhinovirus capsids exhibit conformational flexibility, with empty cavities facilitating "breathing" and genome release upon receptor binding. Transient exposure of internal viral proteins (VP1, VP4) occurs.
- Mouse norovirus (MNV) utilizes a flexible protruding (P) domain that undergoes conformational changes in response to gut molecules like bile salts. This alters receptor binding and immune evasion.
Conclusions:
- Viral protein capsids are dynamic structures, not passive entities.
- Capsid flexibility allows viruses to control genome delivery, interact with host receptors, and evade immune surveillance through conformational changes.
Related Concept Videos
00:56Viral Structure
73.4K
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.
73.4K
01:28Introduction to Virus
940
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...
940
01:30Lytic Cycle of Bacteriophages
77.0K
Bacteriophages, also known as phages, are specialized viruses that infect bacteria. A key characteristic of phages is their distinctive “head-tail” morphology. A phage begins the infection process (i.e., lytic cycle) by attaching to the outside of a bacterial cell. Attachment is accomplished via proteins in the phage tail that bind to specific receptor proteins on the outer surface of the bacterium. The tail injects the phage’s DNA genome into the bacterial cytoplasm. In the...
77.0K
01:26Size and Structure of Viral Genomes
537
Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...
537
01:10Retrovirus Life Cycles
48.9K
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...
48.9K
00:50What are Viruses?
127.0K
Overview
127.0K