Crystal structure of a CAP-DNA complex: the DNA is bent by 90 degrees.
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Schultz SC, Shields GC, Steitz TA
Crystal structure of a CAP-DNA complex: the DNA is bent by 90 degrees.
Science. 1991 Aug 30;253(5023):1001-7.
- PubMed ID
- 1653449 [ View in PubMed]
- 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.