Binding of <i>lac</i> repressor induces different conformational changes on operator and non‐operator DNAs

Culard, Françoise; Maurizot, Jean‐Claude

doi:10.1016/0014-5793(82)80724-2

Cited by 20 publications

(13 citation statements)

References 18 publications

(19 reference statements)

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“…The general direction of the CD change appears to be quite similar to the one induced by the lac repressor on lac operator DNA, because the amplitude of the positive CD band is increased in both cases [9,10]. A similar general behaviour of repressors with respect to DNA binding may be anticipated since the DNA binding domains of different repressors show sequence and structure homologies [21][22][23].…”

Section: _7mentioning

confidence: 64%

“…Figure 5 shows the difference CD spectrum obtained by subtracting the protein and 70 bp DNA spectra from the CD of the complex. As was argued before, the contribution of structural changes of the protein to this difference spectrum is probably negligible [9][10][11][12]. Therefore, the altered CD may be interpreted to reflect a structural change of the DNA induced by complex formation with the TET repressor.…”

Section: _7mentioning

confidence: 65%

“…In detail, however, several differences are noticed between the interaction of lac repressor with lac operator [9,10] and TET repressor with its operator sequence. To distinguish specific and non-specific binding of the lac repressor to DNA, Coulard and Maurizot [9,10] used a 25 bp DNA for specific and a plasmid DNA for non-specific binding.…”

Section: _7mentioning

confidence: 99%

“…To distinguish specific and non-specific binding of the lac repressor to DNA, Coulard and Maurizot [9,10] used a 25 bp DNA for specific and a plasmid DNA for non-specific binding. The difference CD spectra are clearly distinct for these two DNAs.…”

Section: _7mentioning

confidence: 99%

“…In order to address this question the interaction of the lac repressor with lac operator DNA [9,10] and cyclic AMP receptor protein with lac operon DNA [11,12] has been studied by CD spectroscopy. The CD changes of the target DNA induced by these two proteins are different indicating different structural perturbations of the DNA. In this article we describe the changes in the CD spectrum of a short DNA fragment containing the tandem tet operator arrangement [4] with only little flanking DNA induced by complex formation with the TET repressor.…”

Section: Introductionmentioning

confidence: 99%

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TET repressortetoperator complex formation induces conformational changes in thetetoperator DNA

Atschmied

Hillen

1984

Nucl Acids Res

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The structural changes of the tet operator DNA upon binding of the TET repressor protein are examined by circular dichroism. For this purpose a 70 bp DNA fragment was prepared which contains both tet operators. About 67% o'f the base pairs of this DNA are involved in specific interaction with the TET repressor.A rather large change in the CD of the DNA is induced by binding of the TET repressor. The shape of the CD difference spectrum is similar to the respective difference found for the lac operator DNA upon complex formation with the lac repressor. However, the effect induced by the TET repressor on tet operator DNA seems to comprise both the specific and non-specific effect of the lac repressor on the structure of DNA [Culard, F. and Maurizot, J.C. (1981) Nucl. Acids Res. 9, 5157-5184]. Specificity of binding is confirmed by the lack of any effect of the TET repressor on the CD of a 95 bp lac operator containing DNA fragment, by the reduced mobility of TET repressor-tet operator complexes on polyacrylamid gels under CD conditiones, and by a titration experiment of tet operator DNA with TET repressor employing the CD change. The latter experiment reveals a stoichiometry of four TET repressors per tet operon control region.

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Section: _7mentioning

confidence: 64%

Section: _7mentioning

confidence: 65%

Section: _7mentioning

confidence: 99%

Section: _7mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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TET repressortetoperator complex formation induces conformational changes in thetetoperator DNA

Atschmied

Hillen

1984

Nucl Acids Res

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Interaction between the lac operator and the lac repressor headpiece: fluorescence and circular dichroism studies.

Culard¹,

Schnarr²,

Maurizot³

1982

The EMBO Journal

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The interaction between the lac repressor headpiece and a small operator DNA fragment has been examined by fluorescence and circular dichroism (c.d.) measurements. Binding of the headpiece to the DNA fragment induces a strong quenching of the fluorescence of its tyrosine residues. Quantitative analysis of the fluorescence data demonstrates that, in a first step, two headpieces bind very strongly to the DNA fragment then weaker binding occurs. C.d. demonstrates that the binding induces conformational changes of the DNA. The c.d. change produced upon binding of the first two headpieces differs from that induced upon binding of two further headpieces . Binding of the second pair of headpieces is similar to non‐specific binding to non‐operator DNA. The conformation of the operator DNA in the presence of two headpieces differs drastically from that in presence of lac repressor. Addition of the core to the lac operator does not induce any conformational change of the nucleic acids. These results are discussed with respect to the relative roles of core and headpieces in the lac repressor‐lac operator interaction.

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Mutant I12X86 Versus Wild-Type Lac Repressor Photochemistry

et al. 1991

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Binding of lac repressor induces different conformational changes on operator and non‐operator DNAs

Cited by 20 publications

References 18 publications

TET repressortetoperator complex formation induces conformational changes in thetetoperator DNA

TET repressortetoperator complex formation induces conformational changes in thetetoperator DNA

Interaction between the lac operator and the lac repressor headpiece: fluorescence and circular dichroism studies.

Mutant I12X86 Versus Wild-Type Lac Repressor Photochemistry

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