The lac repressor hinge helix in context: The effect of the DNA binding domain and symmetry

Danielle Seckfort, Gillian C. Lynch, B. Montgomery Pettitt

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The Lac system of genes has been an important model system in understanding gene regulation. When the dimer lac repressor protein binds to the correct DNA sequence, the hinge region of the protein goes through a disorder to order transition. The hinge region is disordered when binding to nonoperator sequences. This region of the protein must pay a conformational entropic penalty to order when it is bound to operator DNA. Structural studies show that this region is flexible. Previous simulations showed that this region is disordered when free in solution without the DNA binding domain present. Our simulations corroborate that this region is extremely flexible in solution, but we find that the presence of the DNA binding domain proximal to the hinge helix and salt make the ordered conformation more favorable even without DNA present.

Original languageEnglish (US)
Article number129538
JournalBiochimica et Biophysica Acta - General Subjects
Issue number4
StatePublished - Apr 2020


  • Disorder to order transition
  • Disordered proteins
  • LacI
  • MD simulations
  • Metadynamics
  • Protein
  • Salt stability

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology


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