Proteins from the Prokaryotic Nucleoid. Structural and Functional Characterization of the Escherichia coli DNA-Binding Proteins NS (HU) and H-NS

Gualerzi, Claudio O.; Losso, Maria Adele; Lammi, M.; Friedrich, K.; Pawlik, R. T.; Canonaco, Maria A.; Gianfranceschi, G.; Pingoud, Alfred; Pon, Cynthia L.

doi:10.1007/978-3-642-71266-1_10

Cited by 32 publications

(19 citation statements)

References 61 publications

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“…Second, like H-NS, HU is reported to constrain fewer supercoils and to bind along the entire length of DNA fragments when present at high protein:DNA ratios (Rouviere-Yaniv and Gros, 1975;Rouviere-Yaniv et al, 1979). Third, the ability of both proteins to constrain supercoils is sensitive to ionic strength (this study; Rouviere-Yaniv et al, 1979 H-NS is generally considered to be a relatively non-specific DNA-binding protein (Spassky et al, 1984;Gualerzi et al, 1986). This has raised the question of how it can affect transcription from a specific subset of promoters.…”

Section: Dnase I Footprinting Of H-ns In the Prou Promoter Regionmentioning

confidence: 83%

“…Assuming that all of the added protein is bound to DNA, this saturated complex consists of one H-NS dimer per 16 bp. Previous reports, based on fluorescence studies, suggested that H-NS forms a saturated complex at a ratio of about one H-NS dimer for every 40 bp (Gualerzi et al, 1986;Friedrich et al, 1988). Furthermore, in the saturated complex, DNA supercoils are not constrained and the overall length of the DNA molecule in the saturated complex is not altered by the bound H-NS, implying that the DNA is not wrapped or significantly compacted.…”

Section: Dnase I Footprinting Of H-ns In the Prou Promoter Regionmentioning

confidence: 91%

“…At the highest H-NS concentrations, at which supercoils were no longer constrained, DNA binding was still observed. These highest concentrations of H-NS approximated to a saturated H-NS -DNA complex (see below) although, given the estimated amount of H-NS per cell (Spassky et al, 1984;Gualerzi et al, 1986), are unlikely to reflect the situation in vivo (see Discussion).…”

Section: H-ns Constrains Dna Supercoils In Vitromentioning

confidence: 98%

“…H-NS is a neutral 15.6 kDa protein which is unrelated to any other known DNA-binding protein (reviewed by Higgins et al, 1990a). Several lines of evidence point to a role for H-NS as a structural component of bacterial chromatin: (i) H-NS is present at -20 000 copies per cell, sufficiently abundant to cover a significant proportion of chromosomal DNA (Lammi et al, 1984); (ii) H-NS binds to DNA with little sequence-specificity (Spassky et al, 1984;Gualerzi et al, 1986), although it has increased affinity for intrinsically curved DNA (Yamada et al, 1990;OwenHughes et al, 1992); (iii) H-NS compacts DNA in vitro (Spassky et al, 1984) and in vivo (Spurio et al, 1992); (iv) the linking number of plasmid DNA is altered in hns mutants Dorman et al, 1990; Hinton et al, 1992;Owen-Hughes et al, 1992); (v) hns mutations (previously designated osmZ, drdX, bglY, pilG or virR; Hulton et al, 1990;Goransson et al, 1990;May et al, 1990), alter the frequencies of chromosomal deletion, transposition and site-specific recombination events Lejeune and Danchin, 1990;Falconi et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

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The chromatin-associated protein H-NS alters DNA topology in vitro.

et al. 1994

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Section: Dnase I Footprinting Of H-ns In the Prou Promoter Regionmentioning

confidence: 83%

Section: Dnase I Footprinting Of H-ns In the Prou Promoter Regionmentioning

confidence: 91%

Section: H-ns Constrains Dna Supercoils In Vitromentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The chromatin-associated protein H-NS alters DNA topology in vitro.

et al. 1994

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“…Various lines of evidence suggest that DNAbinding proteins, functionally similar to histones, may play an important role in the structural organization of the bacterial nucleoid (review [1][2][3]). Among these proteins the most abundant is NS (HU).…”

Section: Introductionmentioning

confidence: 99%

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

Friedrich¹,

Gualerzi²,

Lammi³

et al. 1988

FEBS Letters

Self Cite

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The interaction between nucleic acids and Escherichia coil 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 x SSC binds DNA with an apparent Ka" 1.1 x 104 M -~ -bp-L 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.

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Structure and dynamics of the DNA binding protein HU from Bacillus stearothermophilus by NMR spectroscopy

Boelens¹,

Vis²,

Vorgias³

et al. 1996

Biopolymers

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The DNA‐binding protein HU from Bacillus stearothermophilus (HUBst) is a dimer with a molecular weight of 19.5 kDa that is capable of bending DNA. An x‐ray structure has been determined previously [Tanaka et al. (1984) Nature, Vol. 310, pp. 376–381], but no structure could be established for a large part of the supposed DNA‐binding β‐arms. Distance geometry and restrained molecular dynamics using nmr restraints were used to generate a set of 25 structures. These structures display a backbone rms deviation (RMSD) of 0.36 Å for the well‐defined region (residues 2–54 and 75–90). The structure of the core is very similar to that observed in the x‐ray structure, with a pairwise RMSD of 1.06 Å. The structure of the β‐hairpin arm contains a double flip‐over at the prolines in the two strands of the β‐arm. Heteronuclear 15N relaxation measurements indicate that the β‐arm and the tip of the β‐arm is flexible. This explains the disorder observed in the solution and x‐ray structures of the β‐arm with respect to the core of the protein. Overlayed onto itself the β‐arm is better defined, with an backbone RMSD of 1.0 Å calculated for residues 54–59 and 69–74. The tip of the arm adopts a well‐defined 4 : 6 β‐hairpin conformation. Changes in amide 15N and 1H chemical shifts upon titrating DNA are most pronounced for the residues in the β‐hairpin arm and for the residues in the second half of the third α‐helix. Heteronuclear 15N relaxation data for free and complexed HUBst show that the arms become structured upon DNA binding. Together with chemically induced nuclear polarization measurements on a mutant HUBst (M69Y; V76Y) this shows that the β‐hairpin arm is involved in direct DNA interaction. © 1997 John Wiley & Sons, Inc. Biopoly 40: 553–559, 1996

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Proteins from the Prokaryotic Nucleoid. Structural and Functional Characterization of the Escherichia coli DNA-Binding Proteins NS (HU) and H-NS

Cited by 32 publications

References 61 publications

The chromatin-associated protein H-NS alters DNA topology in vitro.

The chromatin-associated protein H-NS alters DNA topology in vitro.

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

Structure and dynamics of the DNA binding protein HU from Bacillus stearothermophilus by NMR spectroscopy

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