TY - JOUR
T1 - Arrangement of subunits in assembled histone H4 fibers
AU - Sperling, R.
AU - Amos, L. A.
PY - 1977
Y1 - 1977
N2 - The structure of assembled histone H4 fibers has been studied by analysis of electron micrographs, including optical diffraction. An individual fiber has the appearance of an 80-Å wide ribbon, twisted at intervals of about 330 Å. Thicker fibers which have been observed seem to be bundles of ribbons. In diffraction patterns from both kinds of fiber, layer lines at axial spacings of about 1/55 Å-1, 1/37 Å-1, and 1/27 Å-1 were most consistently observed. The possible arrangements of molecules within the twisted ribbons have been deduced and are found to be fairly closely related. The ribbons appear to consist of two parallel, unstaggered rows of repeating units, which are probably H4 dimers. The similarity between the observed layer line spacings of the H4 fibers and the spacings of the H4 fibers and the spacings of the maxima in x-ray diffraction patterns from whole chromatin suggests that the H4 fibers have a structure related to that of chromatin. Since homogeneous preparations of histones H2A, H2B, and H3, or any mixture of these four histones, can form similar structures, it seems likely that the basic organization of chromatin is determined by a fibrous histone core arround which the DNA is wrapped.
AB - The structure of assembled histone H4 fibers has been studied by analysis of electron micrographs, including optical diffraction. An individual fiber has the appearance of an 80-Å wide ribbon, twisted at intervals of about 330 Å. Thicker fibers which have been observed seem to be bundles of ribbons. In diffraction patterns from both kinds of fiber, layer lines at axial spacings of about 1/55 Å-1, 1/37 Å-1, and 1/27 Å-1 were most consistently observed. The possible arrangements of molecules within the twisted ribbons have been deduced and are found to be fairly closely related. The ribbons appear to consist of two parallel, unstaggered rows of repeating units, which are probably H4 dimers. The similarity between the observed layer line spacings of the H4 fibers and the spacings of the H4 fibers and the spacings of the maxima in x-ray diffraction patterns from whole chromatin suggests that the H4 fibers have a structure related to that of chromatin. Since homogeneous preparations of histones H2A, H2B, and H3, or any mixture of these four histones, can form similar structures, it seems likely that the basic organization of chromatin is determined by a fibrous histone core arround which the DNA is wrapped.
UR - http://www.scopus.com/inward/record.url?scp=0017672152&partnerID=8YFLogxK
U2 - 10.1073/pnas.74.9.3772
DO - 10.1073/pnas.74.9.3772
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C2 - 269431
AN - SCOPUS:0017672152
SN - 0027-8424
VL - 74
SP - 3772
EP - 3776
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 9
ER -