A 1H NMR study of the 79-residue globular domain of chicken erythrocyte histone H5 (GH5) is presented. Using a combination of two-dimensional NMR techniques to demonstrate through-bond and through-space (less than 5 A) connectivities, the resonances of GH5 are assigned in a sequential manner. From a qualitative interpretation of the short-range nuclear Overhauser effects (NOEs) involving the NH and C alpha H protons, it is shown that GH5 has four alpha-helices. The approximate spatial relationship of three of these four helices relative to each other is deduced from the observation of a number of long-range NOEs. The peptide chain outside the helices appears to have little regular secondary structure and no NOEs characteristic of beta-sheets are apparent.
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