What is the triangulation number?
What is the triangulation number?
The triangulation number is defined as the square of the distance between 2 adjacents 5-fold vertices. The triangulation number can be graphically determined with the following drawing arranged from Caspar and Klug (1963).
What is icosahedral structure?
• An icosahedron is a geometric shape with 20 sides, each composed of an equilateral triangle. The sides are composed of viral protein subunits that create a structural unit, which is repeated to form a larger side and the other sides of the icosahedron.
What are the 3 categories of virus particle symmetry?
Virus particles (virions) fall into three main morphological groups characterized by (1) helical symmetry, (2) cubic symmetry, and (3) other symmetries.
What is t number virus?
The capsid is composed 60 asymmetric units made of 1 protein (T=1), for a total of 60 capsid proteins. Icosahedric triangulation number is calculated following Caspar and Klug system. Physical principles in the construction of regular viruses.
How do you calculate triangulation numbers?
The present paper reports two new formulas for calculating triangulation number T. T = L2/l2 and T = 1.45 r2/l2, where L is the distance between pentons, l the distance between any two adjacent capsomeres, r the radius of viral nucleocapsid. The formulas have been verified and applied.
What is the difference between icosahedral and helical?
A helical virus is a virus that has a capsid shaped in a filamentous or rod-shaped structure that has a central cavity that encloses its nucleic acid. An icosahedral virus is a virus consisting of identical subunits that make up equilateral triangles that are in turn arranged in a symmetrical fashion.
What does an icosahedral capsid consists of?
Many virions are spheroidal—actually icosahedral—the capsid having 20 triangular faces, with regularly arranged units called capsomeres, two to five or more along each side; and the nucleic acid is densely coiled within.
What are the type of symmetries of virus?
Self assembly of virus capsids follows two basic patterns: helical symmetry, in which the protein subunits and the nucleic acid are arranged in a helix, and icosahedral symmetry, in which the protein subunits assemble into a symmetric shell that covers the nucleic acid-containing core.
How many Capsomeres are in a capsid?
Capsid. The capsid is an icosahedron of diameter 125–130 nm. It is fashioned from 161 protein capsomeres, which are contributed by 150 hexons and 11 pentons, plus the portal in the 12th pentonal position.
How many types of filoviruses are there?
The family includes six genera. Several filoviruses (e.g., Ebola virus, Marburg virus) are pathogenic for humans and highly virulent. Bats are natural hosts for some filoviruses (e.g., Marburg virus, Ravn virus), whereas others infect fish (e.g., Huángjiāo virus, Xīlǎng virus).
What is the triangulation number of rhinovirus?
The triangulation number of rhinovirus is mathematically T=1. However the structure of the virion closely resembles that of a T=3 virus. Hence these viruses are refered to as having a p=3 meaning they have a pseudo-T=3 number. Note that p=3 is written with a small p and should not be confused with P=3 the class of icosahedra with T=3 symmetry!
What is the taxonomy of the icictv virus?
ICTV Virus Taxonomy Profile: Filoviridae, Journal of General Virology, 100, 911–912. Members of the family Filoviridae produce variously shaped, often filamentous, enveloped virions containing linear negative-sense non-segmented RNA genomes of 15–19 kb (Table 1. Filoviridae ).
Are filoviruses harmful to humans?
Several filoviruses (e.g., Ebola virus, Marburg virus) are pathogenic for humans and highly virulent. Bats are natural hosts for some filoviruses (e.g., Marburg virus, Ravn virus), whereas others infect fish (e.g., Huángjiāo virus, Xīlǎng virus).
