Proteins from the prokaryotic nucleoid Interaction of nucleic acids with the 15 kDa Escherichia coli histone‐like protein H‐NS

FEBS Letters

Pon, C.L.³  Gualerzi, C.O.³  Friedrich, K.³  Lammi, M.¹  Losso, M.A.² 

[1] Laboratory of Genetics, DBC, University of Camerino, I-62032 Camerino (MC Italy;Department of Cell Biology, University of Calabria, I-87036 Arcavacata di Rende, Italy;Max-Planck-Institut für Molekulare Genetik, Abt. Wittmann, D-1000 Berlin 33, Germany

关键词: Bacterial chromatin;    Protein-nucleic acid interaction;    Fluorescence spectroscopy;   

DOI  :  10.1016/0014-5793(88)80826-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The interaction between nucleic acids and Escherichia coli H-NS, an abundant 15 kDa histone-like protein, has been studied by affinity chromatography, nitrocellulose filtration and fluorescence spectroscopy. Intrinsic fluorescence studies showed that the single Trp residue of H-NS (position 108) has a restricted mobility and is located within an hydrophobic region inaccessible to both anionic and cationic quenchers. Binding of H-NS to nucleic acids, however, results in a change of the microenvironment of the Trp residue and fluorescence quenching; from the titration curves obtained with addition of increasing amounts of poly(dA)-poly(dT) and poly(dC)-poly(dG) it can be estimated that an H-NS dimer in 1.5 × SSC binds DNA with an apparent K _a−1.1 × 10⁴ M⁻¹· bp⁻¹. H-NS binds to double-stranded DNA with a higher affinity than the more abundant histone-like protein NS(HU) and, unlike NS, prefers double-stranded to single-stranded DNA and DNA to RNA; both monovalent and divalent cations are required for optimal binding.

【 授权许可】

Unknown