PMID: 9642048

Authors:

Orth P, Cordes F, Schnappinger D, Hillen W, Saenger W, Hinrichs W

Title:

Conformational changes of the Tet repressor induced by tetracycline trapping.

Journal:

J Mol Biol. 1998 Jun 5;279(2):439-47.

Abstract:

The X-ray crystal structure analysis of inducer-free Tet repressor, TetR, at 2.4 A resolution identifies one of two openings of the tunnel-like binding site as the entrance for the inducer tetracycline-Mg2+, [Mg Tc]+. Recognition and binding of the inducer unleashes conformational changes leading to the induced state of TetR. In the first step, the C-terminal turn of alpha-helix 6 unwinds, thereby altering the orientation of alpha-helix 4. This different orientation of alpha-helix 4 is stabilized by a series of hydrogen bonds mediated through a chain of eight water molecules. The alpha-helix 4 connects the DNA-binding domain (alpha-helices 1 to 3) to the rigid TetR core, and thus regulates gene expression through its respective orientations.