Fig. 4. Core histones bind to the same site of LBR, but associate with different sites of the M31 molecule. Competition assays using M31–GST, GST or Nt-LBR–GST, a constant amount of histone H3 and variable amounts of histone H4. The assay was executed as in Figure 3 and the H3 co-sedimenting with each GST fusion protein was detected by ECL/western blotting (for further details see text).