Overproduction of Escherichia coli integration host factor, a protein with nonidentical subunits

Nash, Howard A.; Robertson, Carol A.; Flamm, Eric L.; Weisberg, Robert A.; Miller, Heather G.

doi:10.1128/jb.169.9.4124-4127.1987

Cited by 207 publications

(118 citation statements)

References 17 publications

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“…It has been reported before (Nash et al, 1987) Figure 1) of both subunits are thought to interact with the DNA via the minor groove (Yang and Nash, 1989) and are, therefore, good candidates for these specific contacts. In this paper, we have shown that an IHF fusion protein with two C-terminal regions of HimA binds much better to the DNA than a fusion protein with two C-terminal regions of HimD.…”

Section: Discussionmentioning

confidence: 99%

The HimA and HimD subunits of integration host factor can specifically bind to DNA as homodimers.

et al. 1994

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Section: Discussionmentioning

confidence: 99%

The HimA and HimD subunits of integration host factor can specifically bind to DNA as homodimers.

et al. 1994

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“…Kits for plasmid purification and DNase I footprinting were purchased from Quiagen and Pharmacia, respectively. gd resolvase (Hatfull et al 1989), calf thymus topoisomerase I (Strausfeld & Richter 1989), and E. coli IHF (Nash et al 1987) were purified as described. Purified E. coli Fis was a kind gift from G. Muskhelishvili and R. Kahmann.…”

Section: Enzymes and Reagentsmentioning

confidence: 99%

The resolvase encoded by Xanthomonas campestris transposable element ISXc5 constitutes a new subfamily closely related to DNA invertases

Liu

Hühne

et al. 1998

Genes to Cells

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Background: Conservative site-specific recombination is responsible for the resolution of cointegrates which result during the transposition of class II transposable elements. Resolution is catalysed by a transposonencoded recombinase, resolvase, that belongs to a large family of recombinases, including DNA invertases. Resolvases and the related invertases are likely to employ similar reaction mechanisms during recombination. There are important differences, however. Resolvases require two accessory DNA binding sites within each of the two directly repeated recombination sites. Invertases instead need a host factor, Fis, and an enhancer type DNA sequence, in addition to two inversely orientated recombination sites.

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“…Wild-type and mutant proteins were purified from overexpressing bacteria, as described previously (15,16).…”

Section: Methodsmentioning

confidence: 99%

Compaction of single DNA molecules induced by binding of integration host factor (IHF)

Ali

Amit

Braslavsky

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

116

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We studied the interaction between the integration host factor (IHF), a major nucleoid-associated protein in bacteria, and single DNA molecules. Force-extension measurements of DNA and an analysis of the Brownian motion of small beads tethered to a surface by single short DNA molecules, in equilibrium with an IHF solution, indicate that: (i) the DNA-IHF complex retains a random, although more compact, coiled configuration for zero or small values of the tension, (ii) IHF induces DNA compaction by binding to multiple DNA sites with low specificity, and (iii) with increasing tension on the DNA, the elastic properties of bare DNA are recovered. This behavior is consistent with the predictions of a statistical mechanical model describing how proteins bending DNA are driven off by an applied tension on the DNA molecule. Estimates of the amount of bound IHF in DNA-IHF complexes obtained from the model agree very well with independent measurements of this quantity obtained from the analysis of DNA-IHF crosslinking. Our findings support the long-held view that IHF and other histone-like proteins play an important role in shaping the longscale structure of the bacterial nucleoid.T he genetic material in bacterial cells is organized in a structure called the nucleoid (1-3). In Escherichia coli, this nucleoprotein complex consists of a single circular DNA molecule 4.7 million bp long, RNA, and a large variety of bound proteins. Among these, about 10 so-called histone-like proteins, including HU, integration host factor (IHF), and H-NS (1-3), shape the short-scale structure of the nucleoid by bending DNA locally on binding. These proteins therefore play an important role in compacting the DNA molecule, in addition to other factors such as supercoiling (4), macromolecular crowding (5), and osmotic effects (6).The level of nucleoid-associated proteins changes as a function of bacterial growth. For example, the level of IHF was shown to increase on entry to the stationary phase of growth, becoming one of the major histone-like proteins in the cell (7-10). By binding to specific DNA sites, IHF participates in forming higher-order DNA structures required for replication, sitespecific recombination, phage packaging, and regulation of transcription initiation (8). IHF can also bind to DNA nonspecifically and can be substituted by HU. In fact, IHF and HU possess similar overall structures and share several regions of conserved homologies (11,12).Very little is known about the structural modifications on DNA induced by histone-like proteins in nucleoid formation. In particular, the degree of compaction induced by each of these proteins has not been quantified, and information about the large-scale structure of nucleoprotein complexes is scarce. This deficiency stems in part from the fact that classical techniques used in molecular biology are designed for studying relatively strong DNA-binding sites and cannot appropriately assess the contribution of nonspecific low-affinity interactions. Furthermore, analyses based on electron micr...

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Overproduction of Escherichia coli integration host factor, a protein with nonidentical subunits

Cited by 207 publications

References 17 publications

The HimA and HimD subunits of integration host factor can specifically bind to DNA as homodimers.

The HimA and HimD subunits of integration host factor can specifically bind to DNA as homodimers.

The resolvase encoded by Xanthomonas campestris transposable element ISXc5 constitutes a new subfamily closely related to DNA invertases

Compaction of single DNA molecules induced by binding of integration host factor (IHF)

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