Adenovirus after negative stain electron microscopy - أطلس مختبرات العرب

(A) The capsid reveals the typical isometric ****l made up from 20 equilateral triangular faces. The 252 capsomeres, 12 pentons and the 240 hollow hexon capsomeres are arranged in a T = 25 symmetry pattern vetite (x 400,000). (B) Adenovirus model. Capsomeres are depicted as circles surrounded by an electron dense stain. The inclined axes, h and k, are indicated. The second vertex has indices h = 5, k = 0. The total number of capsomeres C = 10(h2 + hk + k2) + 2 = 252. Capsomere organization is also expressed by the triangulation number, T, the number of unit triangles on each of the 20 faces of the icosahedron. A unit triangle is formed by lines joining the centers of three adjacent capsomeres. T = (h2 + hk + k2) = 25 for adenoviruses, and C = 1OT + 2. The 12 vertex capsomeres are surrounded by 5 other capsomeres each, therefore called penton and show 5-fold rotational symmetry. The penton base consists of 5 identical 85 kD polypeptide chains and extrudes a long antenna-like fiber protein. The 240 hexon capsomeres are trimers of the 120 kD hexon protomere polypeptide