The influence of DNA binding on the backbone dynamics of the yeast cell- cycle protein Mbp1

Pauline B. McIntosh, Ian A. Taylor, Thomas A. Frenkiel, Stephen J. Smerdon, Andrew N. Lane

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Mbp1 is a transcription factor involved in the regulation of the cell cycle in yeast. The N-terminus of this protein contains a DNA binding domain that includes a winged helix-turn-helix motif. The C-terminal 24 residues of this domain (the 'tail') are disordered in the crystal state, but are important for DNA binding. We have measured 15N NMR relaxation rates at 11.75 and 14.1 T to determine the dynamics of the free protein and in its complex with a specific DNA duplex. The dynamics data were quantitatively analysed using both spectral density mapping and the Lipari-Szabo formalism including the effects of chemical exchange and rotational anisotropy. A detailed analysis has been made of the effect of anisotropy, exchange and experimental precision on the recovered motional parameters. The backbone NH relaxation is affected by motions on a variety of time scales from millisecond to tens of picoseconds. The relaxation data show a structured core of 100 residues corresponding to that observed in the crystal state. Within the core of the protein, two regions on either side of the putative recognition helix (helix B) show slow (ca. 0.2 ms) conformational exchange dynamics that are quenched upon DNA binding. The C-terminal 24 residues are generally more dynamic than in the core. However, in the free protein, a stretch of ~8 residues in the middle of the tail show relaxation behaviour similar to that in the core, indicating a structured region. NOEs between Ala 114 in this structured part of the tail and residues in the N-terminal beta strand of the core of the protein demonstrate that the tail folds back onto the core of the protein. In the complex with DNA, the structured part of the tail extends by ca. 3 residues. These data provide a framework for understanding the biochemical data on the mechanism and specificity of DNA binding.

Original languageEnglish
Pages (from-to)183-196
Number of pages14
JournalJournal of Biomolecular NMR
Issue number3
StatePublished - 2000

Bibliographical note

Funding Information:
This work was supported by the Medical Research Council of the U.K. NMR experiments were carried out at the MRC Biomedical NMR Centre, Mill Hill. We thank Dr. Mark Carr for additional experiments at 14.1 T at the University of Kent. We thank Dr. Andrew Atkinson for discussions about spectral density mapping, and Dr. James Feeney for encouragement and support.


  • Backbone dynamics
  • Chemical exchange
  • Mbp1-DNA interaction
  • Spectral density mapping

ASJC Scopus subject areas

  • Biochemistry
  • Spectroscopy


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