title: C-terminal acidic domain of histone chaperone human NAP1 is an efficient binding assistant for histone H2A-H2B, but not H3-H4.
abstract: Nucleosome assembly protein 1 (NAP1) binds both the (H3-H4)2 tetramer and two H2A-H2B dimers, mediating their sequential deposition on DNA. NAP1 contains a C-terminal acidic domain (CTAD) and a core domain that promotes dimer formation. Here, we have investigated the roles of the core domain and CTAD of human NAP1 in binding to H2A-H2B and H3-H4 by isothermal calorimetry and native mass spectrometry and compared them with the roles of yeast NAP1. We show that the hNAP1 and yNAP1 dimers bind H2A-H2B by two different modes: a strong endothermic interaction and a weak exothermic interaction. A mutant hNAP1, but not yNAP1, dimer lacking CTAD loses the exothermic interaction and shows greatly reduced H2A-H2B binding activity. The isolated CTAD of hNAP1 binds H2A-H2B only exothermically with relatively stronger binding as compared with the exothermic interaction observed for the full-length hNAP1 dimer. Thus, the two CTADs in the hNAP1 dimer seem to provide binding assistance for the strong endothermic interaction of the core domain with H2A-H2B. By contrast, in the relatively weaker binding of hNAP1 to H3-H4 as compared with yNAP1, CTAD of hNAP1 has no significant role. To our knowledge, this is the first distinct role identified for the hNAP1 CTAD.
authors: Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
authors: Hideaki
authors: H
authors: Ohtomo
authors: Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
authors: Satoko
authors: S
authors: Akashi
authors: Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
authors: Yoshihito
authors: Y
authors: Moriwaki
authors: Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan.
authors: Mitsuru
authors: M
authors: Okuwaki
authors: Graduate School of Advanced Science and Engineering/RISE, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
authors: Akihisa
authors: A
authors: Osakabe
authors: Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan.
authors: Kyosuke
authors: K
authors: Nagata
authors: Graduate School of Advanced Science and Engineering/RISE, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
authors: Hitoshi
authors: H
authors: Kurumizaka
authors: Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
authors: Yoshifumi
authors: Y
authors: Nishimura
mesh_terms: D001665:Binding Sites; D006657:Histones / Q000378:metabolism*; D006801:Humans; D056490:Nucleosome Assembly Protein 1 / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D015003:Yeasts / Q000378:metabolism
chemical_list: D006657:Histones; D056490:Nucleosome Assembly Protein 1