Neutron Fibre Diffraction Research Articles

Chromatin structure studies using neutron beams

The compositions and structures of the nucleosome and of chromatin higher-order structures are reviewed: It is shown how neutron solvent D20/H20 contrast-variation studies of nucleosome core particles in solution has been valuable in elucidating core-particle low-resolution structure. Crystallography of core particles by neutron contrast variation of the mother liquor [53] has led to important complementary information to X-ray crystallography and has proposed rather clear arrangements of histone dimers in the structure. Future studies of chromatosomes and modified nucleosome core particles will benefit from the neutron contrast variation method and its complementarity to X-ray crystallography. Neutron fibre diffraction and solution-scattering studies of multinucleosomes has shown the importance of D2O/H20 contrast variation and the excellent small-angle coverage of neutron apparatus. The current models of chromatin higher-order structure consisting of a coil of nucleosomes with a pitch ~ 11 nm, a diameter ~ 33 nm and 6 to 8 nucleosomes for 10 nm length of coil have been established with considerable input from neutron scattering techniques.