10 research outputs found
Structures of Spherical Viral Capsids as Quasicrystalline Tilings
Spherical viral shells with icosahedral symmetry have been considered as
quasicrystalline tilings. Similarly to known Caspar-Klug quasi-equivalence
theory, the presented approach also minimizes the number of conformations
necessary for the protein molecule bonding with its neighbors in the shell, but
is based on different geometrical principles. It is assumed that protein
molecule centers are located at vertices of tiles with identical edges, and the
number of different tile types is minimal. Idealized coordinates of
nonequivalent by symmetry protein positions in six various capsid types are
obtained. The approach describes in a uniform way both the structures
satisfying the well-known Caspar-Klug geometrical model and the structures
contradicting this model.Comment: 8 pages, 2 figures; This version was published in Physics of the
Solid State, 2015, Vol. 57, No.4, pp. 810-81
Chiral Quasicrystalline Order and Dodecahedral Geometry in Exceptional Families of Viruses
On the example of exceptional families of viruses we i) show the existence of
a completely new type of matter organization in nanoparticles, in which the
regions with a chiral pentagonal quasicrystalline order of protein positions
are arranged in a structure commensurate with the spherical topology and
dodecahedral geometry, ii) generalize the classical theory of quasicrystals
(QCs) to explain this organization, and iii) establish the relation between
local chiral QC order and nonzero curvature of the dodecahedral capsid faces.Comment: 8 pages, 3 figure