This entry rerpesnts the N-terminal domain of the histone-binding protein RBBP4. Proteins containing this domain include members from the WD repeat RBAP46 (RBBP7)/RBAP48(RBBP4)/MSI1 family.RBBP4 is a subunit of the chromatin assembly factor 1 (CAF-1) complex. The CAF-1 complex is a conserved heterotrimeric protein complex that promotes histone H3 and H4 deposition onto newly synthesized DNA during replication or DNA repair; specifically it facilitates replication-dependent nucleosome assembly with the major histone H3 (H3.1). This domain is an alpha helix which sits just upstream of the WD40 seven-bladed β-propeller in the human RBBP7 protein. RBBP7 folds into the β-propeller and binds histone H4 in a groove formed between this N-terminal helix and an extended loop inserted into blade six [].