A nuclear-magnetic-resonance study of the globular structure of the H5 histone.

The structure of the globular region of the chicken erythrocyte H5 histone has been studied by 270-MHz proton magnetic resonance. The aromatic resonances have been partially assigned by a combination of selective deuteration and iodination with the nuclear magnetic resonance spectroscopy. Detailed titration studies have revealed interactions between residues in the structure. A technique involving the measurement of small nuclear Overhauser effects has enabled the assignment of the aromatic residues causing the perturbation of the ring-current-shifted methyl resonances occurring in the upfield region of the spectrum. Spin-decoupling experiments on these peaks has enabled a partial assignment of shifted methyl resonances. The results support the notion that the histone H5 globular structure is different from that of the homologous histone H1 molecule.