title: Charge-state-distribution analysis of Bach2 intrinsically disordered heme binding region.
abstract: Bach2 is a transcriptional repressor that plays an important role in the differentiation of T-cells and B-cells. Bach2 is functionally regulated by heme binding, and possesses five Cys-Pro Cys-Pro (CP)-motifs as the heme binding site. To reveal the molecular mechanism of heme binding by Bach2, the intrinsically disordered heme binding region (a.a. 331-520; Bach2331-520) and its CP-motif mutant were prepared and characterized with and without heme, by UV-Vis spectroscopy and thermal profiles. In addition, the charge-state-distributions (CSDs) were assessed by electrospray ionization mass spectrometry. The UV-Vis spectroscopy revealed a lack of five-coordinated heme binding in the CP-motif mutant of Bach2331-520The thermal profile and CSDs of Bach2331-520indicated that heme binding induces the destabilization of Bach2331-520The thermal profile revealed that the wild type Bach2331-520was destabilized more than the CP-motif mutant. The shift in the CSDs by heme binding suggested that heme binding causes Bach2331-520to adopt a more compact conformation. In addition, heme binding to the CP-motif could reduce the flexibility of Bach2331-520Consequently, the five-coordinated heme binding destabilizes Bach2331-520, by reducing the flexibility of the polypeptide chain.
authors.affiliation: Thermo Fisher Scientific, Inc, Yokohama, Japan.
authors.forename: Tomoji
authors.initials: T
authors.lastname: Suenaga
authors.affiliation: Tohoku University, New Industry Creation Hatchery Center, Sendai, Japan.|Division of Biomedical Measurements and Diagnostics, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Watanabe-Matsui
authors.affiliation: Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Yokohama, Japan.
authors.forename: Tamami
authors.initials: T
authors.lastname: Uejima
authors.affiliation: Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan.|AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shima
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Ikeda-Saito
authors.affiliation: Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Yokohama, Japan.
authors.forename: Mikako
authors.initials: M
authors.lastname: Shirouzu
authors.affiliation: Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan.|AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan.|Center for Regulatory Epigenome and Diseases, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Igarashi
authors.affiliation: Division of Biomedical Measurements and Diagnostics, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan kmura@bme.tohoku.ac.jp.|Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Yokohama, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Murayama
mesh_terms: D020816:Amino Acid Motifs; D050976:Basic-Leucine Zipper Transcription Factors / Q000737:chemistry* / Q000235:genetics; D001665:Binding Sites; D006418:Heme / Q000737:chemistry*; D006801:Humans; D064267:Intrinsically Disordered Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: C491123:BACH2 protein, human; D050976:Basic-Leucine Zipper Transcription Factors; D064267:Intrinsically Disordered Proteins; D006418:Heme
keywords: conformational change; electrospray ionization mass spectrometry; heme coordination; intrinsically disordered protein; thermal profiling