Figure 2: A model illustrating the antagonistic effects of H4K16ac and H4K20me1 on chromatin packaging. (a) Chromatin acetylated at H4K16 is loosely packed, due partially to charge neutralization, and partially to effects on interactions with chromatin modifying proteins, such as inhibition of chromatin remodeling by ISWI. (b) Chromatin methylated at H4K20 is tightly packed. In some systems, H4K20me1 and H4K16ac antagonize each other (see text). H4K20me1 also binds to MBT domain containing proteins, which may facilitate chromatin compaction.