title: Phosphorylation-coupled intramolecular dynamics of unstructured regions in chromatin remodeler FACT.
abstract: The intrinsically disordered region (IDR) of a protein is an important topic in molecular biology. The functional significance of IDRs typically involves gene-regulation processes and is closely related to posttranslational modifications such as phosphorylation. We previously reported that the Drosophila facilitates chromatin transcription (FACT) protein involved in chromatin remodeling contains an acidic ID fragment (AID) whose phosphorylation modulates FACT binding to nucleosomes. Here, we performed dynamic atomic force microscopy and NMR analyses to clarify how the densely phosphorylated AID masks the DNA binding interface of the high-mobility-group domain (HMG). Dynamic atomic force microscopy of the nearly intact FACT revealed that a small globule temporally appears but quickly vanishes within each mobile tail-like image, corresponding to the HMG-containing IDR. The lifespan of the globule increases upon phosphorylation. NMR analysis indicated that phosphorylation induces no ordered structure but increases the number of binding sites in AID to HMG with an adjacent basic segment, thereby retaining the robust electrostatic intramolecular interaction within FACT even in the presence of DNA. These data lead to the conclusion that the inhibitory effect of nucleosome binding is ascribed to the increase in the probability of encounter between HMG and the phosphorylated IDR.
authors.affiliation: Department of Mathematical and Life Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Manami
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kodera
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Tsunaka
authors.forename: Masayuki
authors.initials: M
authors.lastname: Oda
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Tanimoto
authors.forename: Toshio
authors.initials: T
authors.lastname: Ando
authors.forename: Kosuke
authors.initials: K
authors.lastname: Morikawa
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Tate
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly; D004247:DNA / Q000378:metabolism; D004330:Drosophila / Q000737:chemistry / Q000378:metabolism; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D055672:Static Electricity
chemical_list: D002352:Carrier Proteins; D029721:Drosophila Proteins; C518656:FACT protein, Drosophila; D009707:Nucleosomes; D004247:DNA