Conformational change in the chromatin remodelling protein MENT

Poh Chee Ong, Sarah J. Golding, Mary C. Pearce, James A. Irving, Sergei Grigoryev, Debbie Pike, Christopher G. Langendorf, Tanya A. Bashtannyk-Puhalovich, Stephen P. Bottomley, James C. Whisstock, Robert N. Pike, Shenna McGowan

Research output: Contribution to journalArticle

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Abstract

Chromatin condensation to heterochromatin is a mechanism essential for widespread suppression of gene transcription, and the means by which a chromatin-associated protein, MENT, induces a terminally differentiated state in cells. MENT, a protease inhibitor of the serpin superfamily, is able to undergo conformational change in order to effect enzyme inhibition. Here, we sought to investigate whether conformational change in MENT is 'fine-tuned' in the presence of a bound ligand in an analogous manner to other serpins, such as antithrombin where such movements are reflected by a change in intrinsic tryptophan fluorescence. Using this technique, MENT was found to undergo structural shifts in the presence of DNA packaged into nucleosomes, but not naked DNA. The contribution of the four Trp residues of MENT to the fluorescence change was mapped using deconvolution analysis of variants containing single Trp to Phe mutations. The analysis indicated that the overall emission spectra is dominated by a helix-H tryptophan, but this residue did not dominate the conformational change in the presence of chromatin, suggesting that other Trp residues contained in the A-sheet and RCL regions contribute to the conformational change. Mutagenesis revealed that the conformational change requires the presence of the DNA-binding 'M-loop' and D-helix of MENT, but is independent of the protease specificity determining 'reactive centre loop'. The D-helix mutant of MENT, which is unable to condense chromatin, does not undergo a conformational change, despite being able to bind chromatin, indicating that the conformational change may contribute to chromatin condensation by the serpin.

Original languageEnglish (US)
Article numbere4727
JournalPloS one
Volume4
Issue number3
DOIs
StatePublished - Mar 6 2009

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Chromatin Assembly and Disassembly
Chromatin
chromatin
Serpins
Proteins
proteins
Tryptophan
tryptophan
Condensation
DNA
Fluorescence
fluorescence
Enzyme inhibition
Mutagenesis
nucleosomes
Antithrombins
Heterochromatin
enzyme inhibition
Nucleosomes
Deconvolution

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Ong, P. C., Golding, S. J., Pearce, M. C., Irving, J. A., Grigoryev, S., Pike, D., ... McGowan, S. (2009). Conformational change in the chromatin remodelling protein MENT. PloS one, 4(3), [e4727]. https://doi.org/10.1371/journal.pone.0004727
Ong, Poh Chee ; Golding, Sarah J. ; Pearce, Mary C. ; Irving, James A. ; Grigoryev, Sergei ; Pike, Debbie ; Langendorf, Christopher G. ; Bashtannyk-Puhalovich, Tanya A. ; Bottomley, Stephen P. ; Whisstock, James C. ; Pike, Robert N. ; McGowan, Shenna. / Conformational change in the chromatin remodelling protein MENT. In: PloS one. 2009 ; Vol. 4, No. 3.
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abstract = "Chromatin condensation to heterochromatin is a mechanism essential for widespread suppression of gene transcription, and the means by which a chromatin-associated protein, MENT, induces a terminally differentiated state in cells. MENT, a protease inhibitor of the serpin superfamily, is able to undergo conformational change in order to effect enzyme inhibition. Here, we sought to investigate whether conformational change in MENT is 'fine-tuned' in the presence of a bound ligand in an analogous manner to other serpins, such as antithrombin where such movements are reflected by a change in intrinsic tryptophan fluorescence. Using this technique, MENT was found to undergo structural shifts in the presence of DNA packaged into nucleosomes, but not naked DNA. The contribution of the four Trp residues of MENT to the fluorescence change was mapped using deconvolution analysis of variants containing single Trp to Phe mutations. The analysis indicated that the overall emission spectra is dominated by a helix-H tryptophan, but this residue did not dominate the conformational change in the presence of chromatin, suggesting that other Trp residues contained in the A-sheet and RCL regions contribute to the conformational change. Mutagenesis revealed that the conformational change requires the presence of the DNA-binding 'M-loop' and D-helix of MENT, but is independent of the protease specificity determining 'reactive centre loop'. The D-helix mutant of MENT, which is unable to condense chromatin, does not undergo a conformational change, despite being able to bind chromatin, indicating that the conformational change may contribute to chromatin condensation by the serpin.",
author = "Ong, {Poh Chee} and Golding, {Sarah J.} and Pearce, {Mary C.} and Irving, {James A.} and Sergei Grigoryev and Debbie Pike and Langendorf, {Christopher G.} and Bashtannyk-Puhalovich, {Tanya A.} and Bottomley, {Stephen P.} and Whisstock, {James C.} and Pike, {Robert N.} and Shenna McGowan",
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Ong, PC, Golding, SJ, Pearce, MC, Irving, JA, Grigoryev, S, Pike, D, Langendorf, CG, Bashtannyk-Puhalovich, TA, Bottomley, SP, Whisstock, JC, Pike, RN & McGowan, S 2009, 'Conformational change in the chromatin remodelling protein MENT', PloS one, vol. 4, no. 3, e4727. https://doi.org/10.1371/journal.pone.0004727

Conformational change in the chromatin remodelling protein MENT. / Ong, Poh Chee; Golding, Sarah J.; Pearce, Mary C.; Irving, James A.; Grigoryev, Sergei; Pike, Debbie; Langendorf, Christopher G.; Bashtannyk-Puhalovich, Tanya A.; Bottomley, Stephen P.; Whisstock, James C.; Pike, Robert N.; McGowan, Shenna.

In: PloS one, Vol. 4, No. 3, e4727, 06.03.2009.

Research output: Contribution to journalArticle

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T1 - Conformational change in the chromatin remodelling protein MENT

AU - Ong, Poh Chee

AU - Golding, Sarah J.

AU - Pearce, Mary C.

AU - Irving, James A.

AU - Grigoryev, Sergei

AU - Pike, Debbie

AU - Langendorf, Christopher G.

AU - Bashtannyk-Puhalovich, Tanya A.

AU - Bottomley, Stephen P.

AU - Whisstock, James C.

AU - Pike, Robert N.

AU - McGowan, Shenna

PY - 2009/3/6

Y1 - 2009/3/6

N2 - Chromatin condensation to heterochromatin is a mechanism essential for widespread suppression of gene transcription, and the means by which a chromatin-associated protein, MENT, induces a terminally differentiated state in cells. MENT, a protease inhibitor of the serpin superfamily, is able to undergo conformational change in order to effect enzyme inhibition. Here, we sought to investigate whether conformational change in MENT is 'fine-tuned' in the presence of a bound ligand in an analogous manner to other serpins, such as antithrombin where such movements are reflected by a change in intrinsic tryptophan fluorescence. Using this technique, MENT was found to undergo structural shifts in the presence of DNA packaged into nucleosomes, but not naked DNA. The contribution of the four Trp residues of MENT to the fluorescence change was mapped using deconvolution analysis of variants containing single Trp to Phe mutations. The analysis indicated that the overall emission spectra is dominated by a helix-H tryptophan, but this residue did not dominate the conformational change in the presence of chromatin, suggesting that other Trp residues contained in the A-sheet and RCL regions contribute to the conformational change. Mutagenesis revealed that the conformational change requires the presence of the DNA-binding 'M-loop' and D-helix of MENT, but is independent of the protease specificity determining 'reactive centre loop'. The D-helix mutant of MENT, which is unable to condense chromatin, does not undergo a conformational change, despite being able to bind chromatin, indicating that the conformational change may contribute to chromatin condensation by the serpin.

AB - Chromatin condensation to heterochromatin is a mechanism essential for widespread suppression of gene transcription, and the means by which a chromatin-associated protein, MENT, induces a terminally differentiated state in cells. MENT, a protease inhibitor of the serpin superfamily, is able to undergo conformational change in order to effect enzyme inhibition. Here, we sought to investigate whether conformational change in MENT is 'fine-tuned' in the presence of a bound ligand in an analogous manner to other serpins, such as antithrombin where such movements are reflected by a change in intrinsic tryptophan fluorescence. Using this technique, MENT was found to undergo structural shifts in the presence of DNA packaged into nucleosomes, but not naked DNA. The contribution of the four Trp residues of MENT to the fluorescence change was mapped using deconvolution analysis of variants containing single Trp to Phe mutations. The analysis indicated that the overall emission spectra is dominated by a helix-H tryptophan, but this residue did not dominate the conformational change in the presence of chromatin, suggesting that other Trp residues contained in the A-sheet and RCL regions contribute to the conformational change. Mutagenesis revealed that the conformational change requires the presence of the DNA-binding 'M-loop' and D-helix of MENT, but is independent of the protease specificity determining 'reactive centre loop'. The D-helix mutant of MENT, which is unable to condense chromatin, does not undergo a conformational change, despite being able to bind chromatin, indicating that the conformational change may contribute to chromatin condensation by the serpin.

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