Preferential binding of E.coli histone-like protein HUα to negatively supercoiled DNA

• Published in: Nucleic acids research Vol. 20; no. 7; pp. 1553 - 1558
• Main Authors: Shindo, Heisaburo, Furubayashi, Arata, Shimizu, Mitsuhiro, Miyake, Masaki, Imamoto, Fumio
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 11.04.1992
• Subjects: Bacterial Proteins - metabolism; DNA, Superhelical - metabolism; DNA-Binding Proteins - metabolism; Electrophoresis, Agar Gel; Escherichia coli - metabolism; Nucleic Acid Conformation; Osmium Tetroxide
• DOI: 10.1093/nar/20.7.1553
• ISSN: 0305-1048

Binding specificity of histone-like HUα protein to supercoiLed DNA was examined by gel retardation assay and chemical probing with OsO4. The latter method was proved to be a unique means for detecting torsional tension restrained in supercoiied piasmid in the presence of HUα. It was shown that HUα protein has preferential affinity to negatively supercoiied DNA relative to relaxed, nicked and linearized DNAs. There were two modes for binding of HUα to the supercoiied DNA: one was the binding associated with topological changes in DNA and the other was relatively strong binding, probably specific to certain particular structures of DNA. It was suggested that HU in vivo interacts preferentially with the regions deformed under torsional stress or with the metabolically active regions along DNA.