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Related Concept Videos

DNA Bacteriophages01:26

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
Lytic Cycle of Bacteriophages01:30

Lytic Cycle of Bacteriophages

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 lytic replication...
Intracellular Movement of Viruses and Bacteria01:10

Intracellular Movement of Viruses and Bacteria

Intracellular bacteria and viruses often comprise a group of highly infectious pathogens that can cause several diseases. Bacterial pathogens include those belonging to the genus Rickettsia responsible for conditions such as rocky mountain spotted fever and the Mediterranean spotted fever; Chlamydia, a genus responsible for a sexually transmitted disease; Coxiella burnetii, an agent responsible for Q fever. Viral pathogens include vaccinia—a poxvirus, and herpes simplex virus—a virus that...
Viral Replication: Lytic Cycle01:20

Viral Replication: Lytic Cycle

Bacteriophages, or phages, are viruses that specifically infect bacteria. Among them, T-even bacteriophages, such as T4, exhibit a well-characterized lytic replication cycle in Escherichia coli (E. coli). This process ensures the rapid proliferation of the virus while ultimately leading to the destruction of the bacterial host.Attachment and DNA InjectionThe infection process begins with the recognition and binding of the T4 phage to the E. coli cell surface. Tail fibers of the phage...
Lysogenic Cycle of Bacteriophages00:43

Lysogenic Cycle of Bacteriophages

In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage. Some prophages can re-activate and enter the lytic cycle. This often occurs in response to a perturbation, such as DNA damage, but can also transpire in the absence of...
The Replisome03:01

The Replisome

DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...

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Updated: Jul 3, 2026

Isolation and Genome Analysis of Single Virions using 'Single Virus Genomics'
08:31

Isolation and Genome Analysis of Single Virions using 'Single Virus Genomics'

Published on: May 26, 2013

The bacteriophage DNA packaging motor.

Venigalla B Rao1, Michael Feiss

  • 1Department of Biology, The Catholic University of America, Washington, D.C. 20064, USA. rao@cua.edu

Annual Review of Genetics
|August 9, 2008
PubMed
Summary

Large DNA viruses use a powerful ATP-driven motor, terminase, to package their genomes into shells. This motor shares similarities with other DNA-processing enzymes, suggesting a common evolutionary origin.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Virology

Background:

  • Large double-stranded DNA (dsDNA) bacteriophages utilize an ATP-powered DNA translocation machine for genome packaging.
  • Key components include the prohead (empty shell), portal protein, and the terminase enzyme.
  • Terminase possesses both translocation ATPase and concatemer-cutting endonuclease activities.

Purpose of the Study:

  • To explore the mechanism of viral genome packaging by the terminase enzyme.
  • To investigate the structural and functional similarities between viral terminases and other motor proteins.
  • To understand the evolutionary relationship between bacteriophage and herpesvirus DNA packaging systems.

Main Methods:

  • Review of existing literature on DNA translocation mechanisms.

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Kinetics of Lagging-strand DNA Synthesis In Vitro by the Bacteriophage T7 Replication Proteins

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Following Cell-fate in E. coli After Infection by Phage Lambda
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Following Cell-fate in E. coli After Infection by Phage Lambda

Published on: October 14, 2011

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Last Updated: Jul 3, 2026

Isolation and Genome Analysis of Single Virions using 'Single Virus Genomics'
08:31

Isolation and Genome Analysis of Single Virions using 'Single Virus Genomics'

Published on: May 26, 2013

Kinetics of Lagging-strand DNA Synthesis In Vitro by the Bacteriophage T7 Replication Proteins
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Kinetics of Lagging-strand DNA Synthesis In Vitro by the Bacteriophage T7 Replication Proteins

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Following Cell-fate in E. coli After Infection by Phage Lambda
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  • Analysis of structural and sequence homology between terminases, portal proteins, and helicases.
  • Consideration of single-molecule biophysics studies on viral packaging motors.

    • Main Results:

    • Terminases exhibit conserved features with portal proteins and shells in tailed bacteriophages and herpesviruses, suggesting a common ancestor.
    • The terminase ATPase domain contains a nucleotide binding fold similar to monomeric helicases.
    • Single-molecule studies reveal the packaging motor to be fast and powerful, with ongoing research to test proposed translocation models.

    Conclusions:

    • The DNA packaging machinery in dsDNA viruses is a sophisticated molecular motor with implications for understanding DNA translocation.
    • Conserved features suggest a shared evolutionary origin for DNA packaging systems in diverse viruses.
    • Further research, including advanced experimental approaches, is crucial for elucidating the precise mechanism of ATP-driven DNA translocation.