title: HMG1 proteins from evolutionary distant organisms distort B-DNA conformation in similar way.
abstract: The abundant high-mobility group proteins 1/2 (HMG1/2) represent a group of potent architectural elements of chromatin. They are able to induce strong bends and untwist DNA. Here, we compared the abilities of diverse HMG1 proteins to distort the B-DNA conformation of 30-base pair DNA fragment. The DNA bending was measured in solution by monitoring fluorescence resonance energy transfer between fluorescence probes attached to opposite ends of the DNA fragment. Various insect and plant proteins which differ in size, in composition of their HMG1-box domains (HMG1-BD), and in composition of the N- and the C-terminally flanking regions were analyzed in these experiments. Despite these structural differences the extent of the induced changes in DNA conformation upon binding to various proteins was similar, as the estimated bend angle was 150+/-20 degrees for all the tested proteins. Our results suggest that a set of highly conserved residues stabilizing the tertiary structure of the HMG1-BD mainly determines the extent of DNA bending in the complex. Even extended positively charged regions flanking the HMG1-BD are apparently not able to influence this conformational distortion of DNA.
authors.affiliation: III. Zoologisches Institut - Entwicklungsbiologie, Universität Göttingen, Humboldtallee 34A, 37073, Göttingen, Germany. jwisnie@gwdg.de
authors.forename: J R
authors.initials: JR
authors.lastname: Wiśniewski
authors.forename: N M
authors.initials: NM
authors.lastname: Krohn
authors.forename: E
authors.initials: E
authors.lastname: Heyduk
authors.forename: K D
authors.initials: KD
authors.lastname: Grasser
authors.forename: T
authors.initials: T
authors.lastname: Heyduk
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002683:Chironomidae; D003432:Cross-Linking Reagents; D004247:DNA / Q000737:chemistry; D019143:Evolution, Molecular; D005454:Fluorescence Polarization; D006609:High Mobility Group Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics; D003313:Zea mays
chemical_list: D003432:Cross-Linking Reagents; D006609:High Mobility Group Proteins; D011994:Recombinant Proteins; D004247:DNA