The globular domain of histone H5 is internally located in the 30 nm chromatin fiber: an immunochemical study.
The location of the globular domain of histone H5 relative to the axis of the 30 nm chromatin fiber was investigated by following the accessibility of this region of the molecule in chicken erythrocyte chromatin to specific antibodies as a function of chromatin structure. Antibodies to the globular domain of H5 as well as their Fab fragments were found to react with chromatin at ionic strengths ranging from 1-80 mM NaCl, the reaction gradually decreasing upon increase of salt concentration. If, however, Fab fragments were conjugated to ferritin, no reaction of the complex with chromatin was observed at salt concentrations higher than 20 mM. The accessibility of the globular part of H5 in unfolded chromatin to the Fab-ferritin complex was also demonstrated with trypsin-digested chromatin. The experiments were carried out by both solid-phase immunoassay and inhibition experiments. The data obtained are consistent with a structure in which the globular domain of H5 is internally located in the 30 nm chromatin fiber.
D000818:Animals; D000906:Antibodies; D002645:Chickens; D002843:Chromatin / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000032:analysis; D004912:Erythrocytes / Q000032:analysis; D006657:Histones / Q000097:blood* / Q000276:immunology; D007140:Immunoglobulin Fab Fragments
D000906:Antibodies; D002843:Chromatin; D000939:Epitopes; D006657:Histones; D007140:Immunoglobulin Fab Fragments