title: Cross-linking of histones with dimethyl 3,3'-dithiobispropionimidate. Interference by a one-end reaction modifying histones at lysine amino groups.
abstract: We have studied the HClO4-solubility of histones H1 and H5 in hen erythrocyte nuclei after treatment with the cross-linker dimethyl 3,3'-dithiobispropionimidate (DTPI). The amount of acid-soluble, non-cross-linked, H1 and H5 histones was drastically decreased, and that of acid-soluble H1/H5 histone dimers went through an optimum as the DTPI concentration was raised. Incubation of the HClO4-insoluble fraction with 2-mercaptoethanol regenerated the acid-solubility of H1/H5 histones in this fraction. When purified H1/H5 histones were treated with increasing concentrations of DTPI under non-cross-linking conditions, the amount of HClO4-soluble histones also greatly decreased, but to a much lesser extent if the DTPI treatment was followed by reduction with 2-mercaptoethanol. This decrease was inversely correlated to the proportion of amino groups modified. It is concluded that, when the cross-linker was used in large excess, the cross-linking reaction competed with a one-end reaction modifying the histones at lysine amino groups by cross-linker molecules, of which the imidoester groups that had not reacted were hydrolysed. It is suggested that this modification produced the changes in acid-solubility.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002645:Chickens; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006657:Histones / Q000097:blood*; D007096:Imidoesters / Q000494:pharmacology*; D008239:Lysine / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D006657:Histones; D007096:Imidoesters; C007471:dimethyl dithiobispropionimidate; D008239:Lysine