Histone H3 and H4 specific chaperone component of the nuclear histone acetyltransferase B (HAT-B) complex. Involved in chromatin assembly and telomere silencing. Homodimer (PubMed:27618665). The homodimer interacts with a histone tetramer containing H3 and H4; the interaction is direct (PubMed:24946827, PubMed:27618665). The homodimer interacts with heterodimeric histone H2A and H2B; the interaction is direct (PubMed:24946827, PubMed:27618665). Component of the nuclear histone acetyltransferase B (HAT-B) complex composed of at least HAT1, HAT2 and HIF1 (PubMed:14761951, PubMed:15099519). Does not interact with HAT1 in the absence of HAT2 (PubMed:14761951, PubMed:24946827). Interacts with histones H3 and H4 in a HAT1/HAT2 dependent manner (PubMed:14761951, PubMed:15099519). Interaction with heterotetrameric histone H3 and H4 precludes interaction with dimeric histone H2A and H2B, irrespective of the fact that their binding involves non-identical regions of the protein (PubMed:24946827, PubMed:27618665). The N-terminal TPR repeat region contains an acidic patch that is important for interaction with histones (PubMed:24946827, PubMed:27618665). A C-terminal, highly polar region mediates interaction with dimeric histone H2A and H2B, but is not involved in interaction with heterotetrameric histone H3 and H4 (PubMed:27618665). Present with 4550 molecules/cell in log phase SD medium. Belongs to the NASP family.