PMID: 15790859 , Related PDB ids: 2BJV, 2BJW

Authors:

Rappas M, Schumacher J, Beuron F, Niwa H, Bordes P, Wigneshweraraj S, Keetch CA, Robinson CV, Buck M, Zhang X

Title:

Structural insights into the activity of enhancer-binding proteins.

Journal:

Science. 2005 Mar 25;307(5717):1972-5.

Abstract:

Activators of bacterial sigma54-RNA polymerase holoenzyme are mechanochemical proteins that use adenosine triphosphate (ATP) hydrolysis to activate transcription. We have determined by cryogenic electron microscopy (cryo-EM) a 20 angstrom resolution structure of an activator, phage shock protein F [PspF(1-275)], which is bound to an ATP transition state analog in complex with its basal factor, sigma54. By fitting the crystal structure of PspF(1-275) at 1.75 angstroms into the EM map, we identified two loops involved in binding sigma54. Comparing enhancer-binding structures in different nucleotide states and mutational analysis led us to propose nucleotide-dependent conformational changes that free the loops for association with sigma54.