What is the Difference Between T2 and T4 Bacteriophage

The key difference between T2 and T4 bacteriophage is that in T2 bacteriophage, enzyme DNA Topo II is coded by the two genes 39 and 60m, while in T4 bacteriophage, this enzyme is coded by the three genes 39, 60, and 52.

Bacteriophage is a type of virus that infects bacteria. Bacteriophages are bacteria eaters since they destroy host cells once infected. There are many types of bacteriophages with reference to morphology and nucleic acid. T2 bacteriophage and T4 bacteriophage are two such types. Both types infect and kill Escherichia coli.

CONTENTS

1. Overview and Key Difference
2. What is T2 Bacteriophage
3. What is T4 Bacteriophage
4. Similarities – T2 and T4 Bacteriophage
5. T2 vs T4 Bacteriophage in Tabular Form
6. Summary – T2 vsT4 Bacteriophage

What is T2 Bacteriophage?

T2 bacteriophage is a virus that infects and kills E. coli. It is known as enterobacteria-phage T2. Bacteriophage T2 belongs to the phylum Uroviricota, family Myoviridae, genus Tequatrovirus and species Escherichia virus T4. The genome of the T2 bacteriophage consists of linear double-stranded DNA. The ends of the DNA strands consist of repeats. T2 bacteriophage has phage enzymes encoded by the two genes 39 and 60. The 39 protein has ATPase activity, and 60 has a complex formation function.

T2 bacteriophage attaches to the surface of the bacterium by proteins or tail fibers and injects its genetic material (either DNA or RNA) into the host cell. The injected genetic material interferes with the bacterium cell structure and machinery. It uses the bacterium ribosomes to replicate and synthesize viral cellular components such as viral proteins. Therefore, new T2 bacteriophages originate from the infected bacterial cell and become responsible for the lysis of bacterial cells when releasing new viral progeny. New T2 macrophages continue the infection of new bacterial cells.

What is a T4 Bacteriophage?

T4 bacteriophage is a virus that infects E.coli and eventually kills the bacterium. It is known as Escherichia virus T4. T4 bacteriophage is a double-stranded DNA virus. It belongs to the family Myoviridae and sub-family Tevenviridae. T4 bacteriophage goes through the lytic cycle but not the lysogenic cycle. The double-stranded DNA of the T4 bacteriophage is about 169 kbp long. It encodes 289 proteins. The genome of T4 is terminally redundant and consists of eukaryotic similar intron sequences.

Compared to other types of bacteriophages, T4 bacteriophage is a relatively large virus with dimensions of 90 nm width and 200 nm length. The tail portion of the T4 bacteriophage is hollow and passes the nucleic acid to the infecting bacteria upon attachment. The tail is a complex structure in T4 bacteriophages with a high number of proteins for attachment and function. T4 bacteriophage consists of 3 genes to encode viral proteins. They are gene 39, 60, and 52.

What are the Similarities Between T2 and T4 Bacteriophage?

• Both are viruses that infect coli.
• They have double-stranded DNA.
• Both T2 and T4 bacteriophages undergo a lytic cycle causing the death of the bacterium.
• They hijack the bacterial cell mechanism to produce viral proteins.

What is the Difference Between T2 and T4 Bacteriophage?

T2 bacteriophage has two genes 39 and 60, to code DNA Topo II enzyme, while T4 bacteriophage has three genes 39,60, and 52 to code DNA Topo II enzyme. Thus, this is the key difference between T2 and T4 bacteriophage. Moreover, the tail portion of the T2 bacteriophage is not complex when compared to the tail of the T4 bacteriophage.

The below infographic presents the differences between T2 and T4 bacteriophage in tabular form for side by side comparison.

Summary – T2 vs T4 Bacteriophage

Bacteriophage is a type of virus that infects bacteria. During infection, a bacteriophage attaches to a susceptible bacterium, releases genetic material, and infects the host cell. T2 bacteriophage and T4 bacteriophage are two such types. Both types infect and kill Escherichia coli. T2 bacteriophage consists of phage enzymes encoded by two genes 39 and 60. T4 bacteriophage consists of 3 genes to encode viral proteins. They are genes 39, 60, and 52. The tail portion of the T2 bacteriophage is not complex when compared to the tail of the T4 bacteriophage. Both T2 and T4 bacteriophages undergo a lytic cycle causing bacterial cell death. So, this is the summary of the difference between T2 and T4 bacteriophage.

Reference:

1. “Bacteriophage.” Encyclopædia Britannica, Encyclopædia Britannica, Inc.
2. G;, Gary TP; Colowick NE; Mosig. “A Species Barrier between Bacteriophages T2 and T4: Exclusion, Join-Copy and Join-Cut-Copy Recombination and Mutagenesis in the Dctpase Genes.” Genetics, U.S. National Library of Medicine.

Image Courtesy:

1. “Structure of a Myoviridae bacteriophage 2” By Chelsea Bonnain, Mya Breitbart and Kristen N. Buck – extracted from this Commons file (CC BY-SA 4.0) via Commons Wikimedia
2. “T4likevirus virion” By ViralZone, SIB Swiss Institute of Bioinformatics: Tevenvirinae –  (CC BY 4.0) via Commons Wikimedia