Crystal structure of a CAP-DNA complex: the DNA is bent by 90 degrees

Science. 1991 Aug 30;253(5023):1001-7. doi: 10.1126/science.1653449.

Abstract

The 3 angstrom resolution crystal structure of the Escherichia coli catabolite gene activator protein (CAP) complexed with a 30-base pair DNA sequence shows that the DNA is bent by 90 degrees. This bend results almost entirely from two 40 degrees kinks that occur between TG/CA base pairs at positions 5 and 6 on each side of the dyad axis of the complex. DNA sequence discrimination by CAP derives both from sequence-dependent distortion of the DNA helix and from direct hydrogen-bonding interactions between three protein side chains and the exposed edges of three base pairs in the major groove of the DNA. The structure of this transcription factor--DNA complex provides insights into possible mechanisms of transcription activation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Binding Sites
  • Cyclic AMP Receptor Protein / chemistry*
  • Cyclic AMP Receptor Protein / metabolism
  • DNA, Bacterial / chemistry*
  • DNA, Bacterial / metabolism
  • DNA-Directed RNA Polymerases / metabolism
  • Escherichia coli / metabolism
  • Hydrogen Bonding
  • Models, Molecular
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Protein Binding
  • Protein Conformation
  • X-Ray Diffraction / methods

Substances

  • Cyclic AMP Receptor Protein
  • DNA, Bacterial
  • DNA-Directed RNA Polymerases