Related Experiment Video
Updated: Jul 19, 2026

Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
Published on: November 1, 2012
Crystal structure of the met repressor-operator complex at 2.8 A resolution reveals DNA recognition by beta-strands
1Department of Biochemistry and Molecular Biology, University of Leeds, UK.
Abstract:
The crystal structure of the met repressor-operator complex shows two dimeric repressor molecules bound to adjacent sites 8 base pairs apart on an 18-base-pair DNA fragment. Sequence specificity is achieved by insertion of double-stranded antiparallel protein beta-ribbons into the major groove of B-form DNA, with direct hydrogen-bonding between amino-acid side chains and the base pairs. The repressor also recognizes sequence-dependent distortion or flexibility of the operator phosphate backbone, conferring specificity even for inaccessible base pairs.
Related Concept Videos
The DNA Helix
DNA as a Genetic Template
The Replisome
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
Cooperative Binding of Transcription Regulators
Co-activators and Co-repressors
The DNA Helix

