SNAP annotations: PDB entry 1efa

PDB-id

1efa; DSSR-derived features in text and JSON formats; DNAproDB

Class

transcription-DNA

Method

X-ray (2.6 Å)

Summary

Crystal structure of the lac repressor dimer bound to operator and the anti-inducer onpf

Reference

Bell CE, Lewis M (2000): "A closer view of the conformation of the Lac repressor bound to operator." Nat.Struct.Biol., 7, 209-214. doi: 10.1038/78907.

Abstract

Crystal structures of the Lac repressor, with and without isopropyithiogalactoside (IPTG), and the repressor bound to operator have provided a model for how the binding of the inducer reduces the affinity of the repressor for the operator. However, because of the low resolution of the operator-bound structure (4.8 A), the model for the allosteric transition was presented in terms of structural elements rather than in terms of side chain interactions. Here we have constructed a dimeric Lac repressor and determined its structure at 2.6 A resolution in complex with a symmetric operator and the anti-inducer orthonitrophenylfucoside (ONPF). The structure enables the induced (IPTG-bound) and repressed (operator-bound) conformations of the repressor to be compared in atomic detail. An extensive network of interactions between the DNA-binding and core domains of the repressor suggests a possible mechanism for the allosteric transition.