X-ray diffraction analysis of crystals containing twofold symmetric nucleosome core particles.
Nucleosome core particles containing a DNA palindrome and purified chicken erythrocyte histone octamer have been reconstituted and crystallized. The dyad symmetry of the palindrome extends the dyad symmetry of the histone octamer to result in a twofold symmetric particle. This ensures that the structure determined by X-ray diffraction will yield a true representation of the DNA strand rather than the twofold averaged structure which would result from using a non-palindromic DNA sequence. The crystals provide isotropic diffraction to 3.2 A with observed reflections extending to d spacings of about 2.8 A using a rotating-anode Cu Kalpha X-ray source. Although the DNA palindrome is a factor contributing to the quality of the diffraction data, another significant factor is an improved preparative technique which enriches for correctly phased nucleosome core particles.
The University of Tennessee/Oak Ridge, Graduate School of Biomedical Sciences, Oak Ridge National Laboratory, 37831-8077, USA.
J M
JM
Harp
E C
EC
Uberbacher
A E
AE
Roberson
E L
EL
Palmer
A
A
Gewiess
G J
GJ
Bunick