Tectivirus
Encyclopedia
The Tectiviridae is a family of double stranded DNA viruses that infect bacteria
and archea. Tectiviridae have no head-tail structure, but are capable of producing tail-like tubes of ~ 60 x 10 nm upon adsorption or after chloroform
treatment. The name is derived from Latin
tectus (meaning 'covered').
There is a single genus in this family - genus Tectivirus.
The type species is Enterobacteria phage PRD1.
.
The capsid is nonenveloped and has a diameter
of 63 nm icosahedron
structure. The capsid
shells are composed of two layers - an inner and outer capsid.
The inner capsid shell consist of a 5-6 nm flexible shell made from a lipoprotein
vesicle whereas the outer capsid is made up of a smooth, rigid 3 nm thin protein
shell. The outer shell has a pseudo T = 25 symmetry and consists of 240 capsid proteins trimers.
The genome is a single molecule of linear double stranded DNA
of 15 kilobases
in length. It forms a tightly packed coil and encodes several structural proteins. It encodes ~30 proteins that are transcribed in operons.
At least 9 structural proteins are present in the viron.
The genome is ~66 megaDaltons in weigh and constitutes 14-15% of the virion by weight. Lipid
s constitute a further 15% by weight. Carbohydrates are not present.
Capsid proteins polymerize around a lipoprotein vesicle translocated in the cytoplasm by virion assembly factors.
Mature virons are released by lysis.
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
and archea. Tectiviridae have no head-tail structure, but are capable of producing tail-like tubes of ~ 60 x 10 nm upon adsorption or after chloroform
Chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
treatment. The name is derived from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
tectus (meaning 'covered').
There is a single genus in this family - genus Tectivirus.
The type species is Enterobacteria phage PRD1.
Virology
This family of viruses consist of virons with double layers capsids that have apical spikes extending ~20 nanometers (nm) and an unusual internal lipid envelope around the nucleoproteinNucleoprotein
A nucleoprotein is any protein that is structurally associated with nucleic acid .Many viruses harness this protein, and they are known for being host-specific...
.
The capsid is nonenveloped and has a diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
of 63 nm icosahedron
Icosahedron
In geometry, an icosahedron is a regular polyhedron with 20 identical equilateral triangular faces, 30 edges and 12 vertices. It is one of the five Platonic solids....
structure. The capsid
Capsid
A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...
shells are composed of two layers - an inner and outer capsid.
The inner capsid shell consist of a 5-6 nm flexible shell made from a lipoprotein
Lipoprotein
A lipoprotein is a biochemical assembly that contains both proteins and lipids water-bound to the proteins. Many enzymes, transporters, structural proteins, antigens, adhesins, and toxins are lipoproteins...
vesicle whereas the outer capsid is made up of a smooth, rigid 3 nm thin protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
shell. The outer shell has a pseudo T = 25 symmetry and consists of 240 capsid proteins trimers.
The genome is a single molecule of linear double stranded DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
of 15 kilobases
Base pair
In molecular biology and genetics, the linking between two nitrogenous bases on opposite complementary DNA or certain types of RNA strands that are connected via hydrogen bonds is called a base pair...
in length. It forms a tightly packed coil and encodes several structural proteins. It encodes ~30 proteins that are transcribed in operons.
At least 9 structural proteins are present in the viron.
The genome is ~66 megaDaltons in weigh and constitutes 14-15% of the virion by weight. Lipid
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
s constitute a further 15% by weight. Carbohydrates are not present.
Life cycle
After adsorbion to the host's cells surface the viron extruds a tail-tube structure through a vertex for genome delivery into the host.Capsid proteins polymerize around a lipoprotein vesicle translocated in the cytoplasm by virion assembly factors.
Mature virons are released by lysis.