Genus “L5-like viruses“

Type Species	Mycobacterium phage L5	(L5)

Distinguishing Features

Phage DNA has cos sites and codes for a type A (E. coli Pol I) DNA polymerase.

Virion Properties

Morphology

Virions have isometric heads of about 60  nm in diameter and flexible tails of 135 8  nm with a terminal knob and a single short fiber.

Physicochemical and Physical Properties

Virion Mr is 116 10⁶; buoyant density in CsC1 is 1.51  g/cm³; S_20w is 410 (data from Mycobacterium phage phlei). Chloroform sensitivity has been reported in possibly related phages.

Nucleic Acid

Genomes are about 52  kbp in size. The Mycobacterium phage L5 (L5) genome has been fully sequenced and has 52,297  bp. The G+C content is about 63%.

Proteins

Virions contain at least 6 structural proteins (Mr 19-22 to 250 10³), including a major capsid protein of 35 10³. Type A (E. coli Pol I) DNA polymerase is encoded. Amino acid sequences for L5 are available at GenBank and EMBL.

Lipids

Not known.

Carbohydrates

Not known.

Genome Organization and Replication

The genetic map is linear. Related genes cluster together. The genome includes 88 genes and has cohesive ends. Host syntheses are shut off during replication. Transcription of structural genes is rightward.

Biological Properties

Phages are temperate and are specific for mycobacteria. Prophages integrate at specific sites into the bacterial genome.

List of Species Demarcation Criteria in the Genus

Not applicable.

List of Species in the Genus

Official virus species names are in italics. Tentative virus species names, alternative names ( ), strains or serotypes are not italicized. Virus names, genome sequence accession numbers [ ], and assigned abbreviations ( ) are:

Species in the Genus

Mycobacterium phage L5	[Z18946]	(L5)

Tentative Species in the Genus

Mycobacterium phage Leo	(Leo)
Mycobacterium phage minetti	(minetti)
Mycobacterium phage phlei	(GS4E)

About 15 other isolates can tentatively be related to phage L5.