Engineering CatM, a LysR-Type Transcriptional Regulator, to Respond Synergistically to Two Effectors

The simultaneous response of one transcriptional regulator to different effectors remains largely unexplored. Nevertheless, such interactions can substantially impact gene expression by rapidly integrating cellular signals and by expanding the range of transcriptional responses. In this study, similarities between paralogs were exploited to engineer novel responses in CatM, a regulator that controls benzoate degradation in Acinetobacter baylyi ADP1. One goal was to improve understanding of how its paralog, BenM, activates transcription in response to two compounds (cis,cis-muconate and benzoate) at levels significantly greater than with either alone. Despite the overlapping functions of BenM and CatM, which regulate many of the same ben and cat genes, CatM normally responds only to cis,cis-muconate. Using domain swapping and site-directed amino acid replacements, CatM variants were generated and assessed for the ability to activate transcription. To create a variant that responds synergistically to both effectors required alteration of both the effector-binding region and the DNA-binding domain. These studies help define the interconnected roles of protein domains and extend understanding of LysR-type proteins, the largest family of transcriptional regulators in bacteria. Additionally, renewed interest in the modular functionality of transcription factors stems from their potential use as biosensors

Natural transformation as a tool in Acinetobacter baylyi: Evolution by amplification of gene copy number

23 p.-6 fig.-1 tab.Pardo wishes to thank the Spanish National Research Council, Reina Sofía Foundation, and Primafrío Foundation for funding under agreement no. 20210510. Research at the University of Georgia in the United States, described in this chapter, was funded by grants from the National Science Foundation (MCB2225858) and the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research, Genomic Science Program (DE-SC0022220). S. Santala would like to thank the Novo Nordisk Foundation (grant NNF21OC0067758) and the Academy of Finland (grant no. 334822 and 347204).Peer reviewe