An allosteric theory of transcription factor induction

Allosteric molecules serve as regulators of cellular activity across all domains of life. We present a general theory of allosteric transcriptional regulation that permits quantitative predictions for how physiological responses are tuned to environmental stimuli. To test the model's predictive power, we apply it to the specific case of the ubiquitous simple repression motif in bacteria. We measure the fold-change in gene expression at different inducer concentrations in a collection of strains that span a range of repressor copy numbers and operator binding strengths. After inferring the inducer dissociation constants using data from one of these strains, we show the broad reach of the model by predicting the induction profiles of all other strains. Finally, we derive an expression for the free energy of allosteric transcription factors which enables us to collapse the data from all of our experiments onto a single master curve, capturing the diverse phenomenology of the induction profiles