A protein-DNA binding mechanism proceeds through multi-state or two-state parallel pathways

J Mol Biol. 2003 Aug 1;331(1):89-99. doi: 10.1016/s0022-2836(03)00720-4.

Abstract

The DNA-binding mechanism of the dimeric C-terminal domain of the papillomavirus E2 protein with its specific DNA target was investigated and shown to proceed through two parallel pathways. A sequential multi-step reaction is initiated by the diffusion-controlled formation of an encounter complex, with no evidence of base sequence discrimination capacity. Following a substantial conformational rearrangement of the protein, a solvent exclusion step leading to the formation of a final protein-DNA complex was identified. This last step involves the largest burial of surface area from the interface and involves the consolidation of the direct readout of the DNA bases. Double-jump stopped-flow experiments allowed us to characterize the sequence of events and demonstrated that a fast-formed consolidated complex can take place through a parallel route. We present the simplest model for the overall mechanism with a description of all the intermediate species in energetic terms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • DNA / chemistry*
  • DNA-Binding Proteins / chemistry*
  • Diffusion
  • Kinetics
  • Oncogene Proteins, Viral / chemistry*
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Tertiary
  • Solvents / chemistry
  • Spectrum Analysis
  • Substrate Specificity
  • Thermodynamics

Substances

  • DNA-Binding Proteins
  • E2 protein, Human papillomavirus type 16
  • Oncogene Proteins, Viral
  • Solvents
  • DNA