Integration host factor (IHF) stimulates binding of the gpNu1 subunit of λ terminase to<i>cos</i>DNA

Shinder, Gayle A.; Gold, Marvin

doi:10.1093/nar/17.5.2005

Cited by 17 publications

(15 citation statements)

References 40 publications

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“…Insertions between R2 and R1 (7-20 bp) and/or deletion of R1 yield phage phenotypically identical to u cos154 suggesting that IHF obviates the need for the R1 element rather than increasing the affinity of gpNu1 for the site. This is consistent with the observation that IHF does not stimulate gpNu1 binding to the R1 element of u cos154 in vitro [25]. Conversely, while phage with point mutations in the R2 element are similarly IHF dependent for growth, deletion of this element is lethal even in IHF + hosts [96].…”

Section: Review Articlesupporting

confidence: 89%

“…Identical footprints are observed in the R3 and R2 region of phage u cos154, but no protection is observed at R1, consistent with the posit that the mutation alters the affinity of gpNu1 for that site [95]. Similar studies have demonstrated that IHF binds strongly to the I1 element in cosB, but only weakly to I2 [26,91,92], and that IHF promotes gpNu1 binding to the R elements [25]. Subsequent studies have demonstrated that point mutations in any of the R elements found within cosB also render the virus IHF dependent for development, with the severity of the mutations following the order R3 \ R2 \ R1 [96].…”

Section: Review Articlesupporting

confidence: 69%

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The terminase enzyme from bacteriophage lambda: a DNA-packaging machine

Catalano

2000

Cellular and Molecular Life Sciences (CMLS)

157

139

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This review focuses on the biochemical, biophysical, and catalytic properties of terminase, an enzyme involved in bacteriophage lambda genome packaging. The holoenzyme possesses ATPase, DNA strand-separation, and site-specific nuclease activities that work in concert to insert a viral genome into the confines of a performed capsid. Moreover, the terminase subunits are part of a series of nucleoprotein complexes involved in genome packaging, including remarkably stable intermediates that transition to a highly mobile DNA packaging 'machine.' Models for the assembly and interconversion of these complexes are presented. Interactions between the catalytic sites in the enzyme complex, and modulation of these catalytic activities as it relates to the assembly and relative stability of the packaging intermediates are discussed. This ordered progression of nucleoprotein intermediates is a common theme in biology as demonstrated by mechanistic similarities between viral DNA packaging, the initiation of chromosomal replication, and the initiation of transcription. Terminase is thus part of a growing number of examples of biological 'machines' or molecular 'motors.'

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Section: Review Articlesupporting

confidence: 89%

Section: Review Articlesupporting

confidence: 69%

The terminase enzyme from bacteriophage lambda: a DNA-packaging machine

Catalano

2000

Cellular and Molecular Life Sciences (CMLS)

157

139

View full text Add to dashboard Cite

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“…A role for IHF in the terminase reaction has been reported previously (43). IHF was reported to bind to several sites in the cos region and imparts a DNA bend of at least 140°c entered at these sites (27).…”

Section: Discussionmentioning

confidence: 62%

“…Replacement of the IHF binding site with intrinsically bent DNA permits efficient X att recombination in the absence of IHF (20). In analogy with IHF stimulation of integrase binding at X att, it has been proposed that IHF induced bending at cos promotes protein-protein contacts between gpNul molecules bound at neighboring sites (27,43 …”

Section: Discussionmentioning

confidence: 99%

HU and integration host factor function as auxiliary proteins in cleavage of phage lambda cohesive ends by terminase

1991

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HU and iategrtion host factor (IHF) are small, basic heterodimeric DNA-binding proteins which participate in transcripion Intatin, DNA replication, and recom . We constructed isogenic Escherichia coli stains in which fIU, THF, or both proteins were absent. Bacteriophage X did not grow in hosts lacing both HU and THE. Phage DNA replication and late gene transcription were normal in the double mutants, but packaging of A DNA was defective. Mature phage DNA molecules were absent, indicating that terminase was unable to linearize K DNA. Phage variants carrying a small substitution near cos or the ohml mutation in the terminase gene, Nul, formed plaques on HU-IHF-strains. We propose that HU or THU is required to establish the higher-order DNA-protein structure at cos that is the substrate for K terminase.DNA-protein complexes with a high degree of organization form at the initiation of DNA replication and are intermediates in several DNA recombination reactions. The ordered structures arise from the concerted assembly of a number of proteins on supercoiled DNA and bring nucleotide sequences located at a distance or on separate molecules into close proximity. In some of these reactions, the DNA bending required to form the complexes is facilitated by low-molecular-weight basic DNA-binding proteins (reviewed by Travers [50]).The best-studied Escherichia coli proteins of this type are the integration host factor (IHF) and HU (reviewed by Drlica and Rouviere-Yaniv [7] and Friedman [14]). IHF is composed of two nonidentical subunits, a and ,B, encoded by the himA (32) and hip (12) genes, respectively. IHF binds in the DNA minor groove (54) and imparts a bend to the DNA in excess of 1400 (27,36,38,49). The binding of IHF to specific DNA sequences at the K attachment site promotes A integration and excision. In a role that is probably related to DNA bending, IHF bound at K promoters can inhibit (22) (10). Although k packaging can take place in THF-hosts, an absolute requirement for IHF can be seen when the phage carries a cos site mutation (cosl54 or cos59) (1,31) or when the host canries a DNA gyrase mutation (15). Phage carrying the ohml mutation in the Nul gene will form plaques on IHF-gyrB hosts (21; also see reference 9).The genes coding for the a and ,B subunits of HU, hupA and hupB, respectively, have recently been cloned (25,26

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“…IHF assists in the utilization of the R sequences by terminase as follows. IHF stimulates ;i assembly in vivo and enhances terminase function in vitro; furthermore many cos mutations render X IHF dependent for plaque formation (Gold and Parris, 1986;Xin and Feiss, 1988;1993;Kosturko etai, 1989;Shinder and Gold, 1989;Mendelson et ai, 1991;Cue and Feiss, 1992a;Xin et ai, 1993). IHF introduces a sharp bend between R3 and R2 (Kosturko etai, 1989), and mutations in 11 abolish IHF stimulation of the X yield (Xin et ai, 1993).…”

Section: Dna-protein Interactions: Interactions Of Gpnui and Ihe Withmentioning

confidence: 99%

Virus DNA packaging: the strategy used by phage λ

Catalano

Cue

Feiss

1995

Molecular Microbiology

185

187

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SummaryPhage I, like a number of other iarge DNA bacteriophages and the herpesviruses, produces concatemeric DNA during DNA replication. The concatemeric DNA is processed to produce unit-length, virion DNA by cutting at specific sites along the cortcatemer. DNA cutting is co-ordinated with DNA packaging, the process of translocation of the cut DNA into the preformed capsid precursor, the prohead. A key player in the X DNA packaging process is the phage-encoded enzyme terminase, which is involved in (i) recognition of (he concatemeric k DNA; (fi) initiation of packaging, which includes the introduction of staggered nicks at cosN to generate the cohesive ends of virion DNA and the binding of the proliead; (iii) DNA packaging, possibly including the ATP-driven DNA translocation; and (iv) following translocation, the cutting of the terminal cosN lo complete DNA packaging. To one side of cosN is the site cosB, which plays a role in the initiation of packaging; along with ATP, cosB stimulates the efficiency and adds fidelity to the endonuclease activity of terminase in cutting cosN. cosB is essential for the formation of a post-cleavage complex with terminase, complex I, that binds the prohead, forming a ternary assembly, complex II. Terminase interacts with cosN through its iarge subunit, gpA, and the small terminase subunit, gpNu1, interacts with cosB. Packaging follows complex 11 formation. cosN is flanked on the other side by the site cosQ, which is needed for termination, but not initiation, of DNA packaging. cosO is required for cutting of the second cosN, i.e. the cosW at which termination occurs. DNA packaging in X, has aspects that differ from other X DNA transactions. Unlike the site-specific Received

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Integration host factor (IHF) stimulates binding of the gpNu1 subunit of λ terminase tocosDNA

Cited by 17 publications

References 40 publications

The terminase enzyme from bacteriophage lambda: a DNA-packaging machine

The terminase enzyme from bacteriophage lambda: a DNA-packaging machine

HU and integration host factor function as auxiliary proteins in cleavage of phage lambda cohesive ends by terminase

Virus DNA packaging: the strategy used by phage λ

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