Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Size and Structure of Viral Genomes

Size and Structure of Viral Genomes

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...

Viral Structure

Viral 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.

Telomeres and Telomerase

Telomeres and Telomerase

In eukaryotic DNA replication, a single-stranded DNA fragment remains at the end of a chromosome after the removal of the final primer. This section of DNA cannot be replicated in the same manner as the rest of the strand because there is no 3’ end to which the newly synthesized DNA can attach. This non-replicated fragment results in gradual loss of the chromosomal DNA during each cell duplication. Additionally, it can induce a DNA damage response by enzymes that recognize single-stranded...

Retroviruses

Retroviruses

Retroviruses and retrotransposons both insert copies of their genetic elements into the genome of the host cell. Thus, the viral genes are passed on when the host genome is replicated or translated. A typical retroviral DNA sequence contains 3-4 genes that encode the different proteins required for its structural assembly and function as a molecular parasite. This DNA is transcribed into a single mRNA, which is very similar in structure to conventional mRNAs, i.e., it is capped at the 5’...

Conservation of Protein Domains Over Different Proteins

Conservation of Protein Domains Over Different Proteins

Protein domains are small structurally independent units that are part of a single amino acid chain. Although these domains are often structurally independent, they may rely on synergistic effects to perform their functions as part of a larger protein. Protein domains may be conserved within the same organism, as well as across different organisms.
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to...

RNA Structure

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA) involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Efficient Glare Suppression Network for Nighttime Images with Lightweight Parallel Attention and Ghost Convolution.

Sensors (Basel, Switzerland)·2026

Same author

Structural choreography of bacteriophage N4 ejection proteins and the giant virion-associated RNA polymerase.

Nature communications·2026

Same author

Insights into Genome Ejection by a Therapeutic phiKMV-like Bacteriophage.

bioRxiv : the preprint server for biology·2026

Same author

Trends and insights in non-syndromic craniosynostosis research globally: a bibliometric analysis of the Web of Science database (2005-2024).

Translational pediatrics·2026

Same author

Species and strain diversity in Staphylococcus drive divergent host responses in human skin.

bioRxiv : the preprint server for biology·2026

Same author

Structural atlas of Pakpunavirus P7-1 reveals determinants of virion stability and genome ejection.

Communications biology·2026

Same journal

Correction: Bulatov et al. Camelpox Virus in Western Kazakhstan: Assessment of the Role of Local Fauna as Reservoirs of Infection. <i>Viruses</i> 2024, <i>16</i>, 1626.

Viruses·2026

Same journal

Correction: Franco et al. Whole Blood Volume-Based Absolute Quantification of HTLV-1 Proviral Load: A Comparative Method Evaluation Study. <i>Viruses</i> 2026, <i>18</i>, 580.

Viruses·2026

Same journal

Correction: Medkour et al. Adenovirus Infections in African Humans and Wild Non-Human Primates: Great Diversity and Cross-Species Transmission. <i>Viruses</i> 2020, <i>12</i>, 657.

Viruses·2026

Same journal

Burden of Malaria and Dengue Across Global, Asian, and Chinese Populations Based on GBD 2021 Data: A Quantitative Assessment of Importation Risks to China.

Viruses·2026

Same journal

First Report of <i>Orthonairovirus songlingense</i> in <i>Haemaphysalis concinna</i> Ticks from Russia.

Viruses·2026

Same journal

Epidemiological and Virological Characteristics of H9N2 Avian Influenza Virus in Jiangsu Province, China, 2024.

Viruses·2026

See all related articles

Search research articles

Related Experiment Video

Updated: Aug 23, 2025

Determining 3'-Termini and Sequences of Nascent Single-Stranded Viral DNA Molecules during HIV-1 Reverse Transcription in Infected Cells

Determining 3'-Termini and Sequences of Nascent Single-Stranded Viral DNA Molecules during HIV-1 Reverse Transcription in Infected Cells

Published on: January 30, 2019

Viral Small Terminase: A Divergent Structural Framework for a Conserved Biological Function.

Ravi K Lokareddy¹, Chun-Feng David Hou¹, Fenglin Li¹

¹Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.

|October 27, 2022

Summary

This summary is machine-generated.

The small terminase subunit (TerS) is crucial for viral genome packaging, despite being dispensable in vitro. This review explores TerS evolution, revealing a flexible framework adapting to diverse viral strategies.

Keywords:

TerS X-ray crystallography bacteriophages cryo-EM herpesviruses terminase subunits viral genome packaging

More Related Videos

Analysis of Group IV Viral SSHHPS Using In Vitro and In Silico Methods

Analysis of Group IV Viral SSHHPS Using In Vitro and In Silico Methods

Published on: December 21, 2019

Assembly and Purification of Prototype Foamy Virus Intasomes

Assembly and Purification of Prototype Foamy Virus Intasomes

Published on: March 19, 2018

Related Experiment Videos

Last Updated: Aug 23, 2025

Determining 3'-Termini and Sequences of Nascent Single-Stranded Viral DNA Molecules during HIV-1 Reverse Transcription in Infected Cells

Determining 3'-Termini and Sequences of Nascent Single-Stranded Viral DNA Molecules during HIV-1 Reverse Transcription in Infected Cells

Published on: January 30, 2019

Analysis of Group IV Viral SSHHPS Using In Vitro and In Silico Methods

Analysis of Group IV Viral SSHHPS Using In Vitro and In Silico Methods

Published on: December 21, 2019

Assembly and Purification of Prototype Foamy Virus Intasomes

Assembly and Purification of Prototype Foamy Virus Intasomes

Published on: March 19, 2018

Area of Science:

Virology
Molecular Biology
Structural Biology

Background:

Bacteriophage and herpesvirus genome packaging relies on terminase complexes, comprising large (TerL) and small (TerS) subunits.
TerL's role in DNA packaging and ATP-dependent translocation is well-understood, but TerS function remains enigmatic.
TerS is essential in vivo for viral packaging, yet often dispensable or inhibitory in in vitro experimental settings.

Purpose of the Study:

To review and inventory known small terminase (TerS) structures and functions across various viruses.
To elucidate the evolutionary diversification of TerS and its impact on viral genome packaging strategies.

Main Methods:

Compilation and analysis of existing crystallographic structures of phage TerS proteins.
Leveraging advancements in cryo-electron microscopy (cryo-EM) for structural insights.
Comparative analysis of TerS sequences and quaternary structures.

Main Results:

TerS exhibits significant sequence and structural diversity across different viral families.
Despite variations, TerS subunits appear to function as flexible molecular frameworks.
Minimal conservation in sequence and quaternary structure suggests adaptation to specific packaging mechanisms and conditions.

Conclusions:

The small terminase (TerS) subunit has evolved a flexible framework, allowing functional conservation despite structural diversification.
Understanding TerS evolution provides insights into the adaptability of viral genome packaging machinery.
Further structural and functional studies of TerS are needed to fully comprehend its role in viral replication.