title: Rice HMGB1 protein recognizes DNA structures and bends DNA efficiently.
abstract: We analyzed the DNA-binding and DNA-bending properties of recombinant HMGB1 proteins based on a rice HMGB1 cDNA. Electrophoretic mobility shift assay demonstrated that rice HMGB1 can bind synthetic four-way junction (4H) DNA and DNA minicircles efficiently but the binding to 4H can be completed out by HMGA and histone H1. Conformational changes were detected by circular dichroism analysis with 4H DNA bound to various concentrations of HMGB1 or its truncated forms. T4 ligase-mediated circularization assays with short DNA fragments of 123 bp showed that the protein is capable of increasing DNA flexibility. The 123-bp DNA formed closed circular monomers efficiently in its presence, similar to that in an earlier study on maize HMG. Additionally, our results show for the first time that the basic N-terminal domain enhances the affinity of the plant HMGB1 protein for 4H DNA, while the acidic C-terminal domain has the converse effects.
authors.affiliation: Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Science Drive 4, 117543, Singapore, Singapore.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wu
authors.forename: Wensheng
authors.initials: W
authors.lastname: Zhang
authors.forename: Keng-Hock
authors.initials: KH
authors.lastname: Pwee
authors.forename: Prakash P
authors.initials: PP
authors.lastname: Kumar
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000187:drug effects; D018076:DNA, Complementary / Q000737:chemistry; D024243:HMGB1 Protein / Q000737:chemistry* / Q000494:pharmacology; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D012275:Oryza / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry / Q000494:pharmacology; D016133:Polymerase Chain Reaction
chemical_list: D018076:DNA, Complementary; D024243:HMGB1 Protein; D009838:Oligodeoxyribonucleotides; D010940:Plant Proteins; D004247:DNA