Περίληψη:
The structure of the octameric histone core of the nucleosome has been
determined by x-ray crystallography to a resolution of 3.1 angstrom. The
histone octamer is a tripartite assembly in which a centrally located
(H3-H4)2 tetramer is flanked by two H2A-H2B dimers. It has a complex
outer surface; depending on the perspective, the structure appears as a
wedge or as a flat disk. The disk represents the planar projection of a
left-handed proteinaceous superhelix with almost-equal-to 28 angstrom
pitch. The diameter of the particle is 65 angstrom and the length is 60
angstrom at its maximum and almost-equal-to 10 angstrom at its minimum
extension; these dimensions are in agreement with those reported earlier
by Klug et al. [Klug, A., Rhodes, D., Smith, J., Finch, J. T. &
Thomas, J. O. (1980) Nature (London) 287, 509-516]. The folded histone
chains are elongated rather than globular and are assembled in a
characteristic “handshake” motif. The individual polypeptides share
a common central structural element of the helix-loop-helix type, which
we name the histone fold.
Συγγραφείς:
ARENTS, G
BURLINGAME, RW
WANG, BC
LOVE, WE
MOUDRIANAKIS,
EN
