AraC-like transcriptional activator CuxR binds c-di-GMP by a PilZ-like mechanism to regulate extracellular polysaccharide production.Schaper, S., Steinchen, W., Krol, E., Altegoer, F., Skotnicka, D., Sgaard-Andersen, L., Bange, G., Becker, A.
(2017) Proc. Natl. Acad. Sci. U.S.A. 114: E4822-E4831
- PubMed: 28559336
- DOI: 10.1073/pnas.1702435114
- PubMed Abstract:
Cyclic dimeric GMP (c-di-GMP) has emerged as a key regulatory player in the transition between planktonic and sedentary biofilm-associated bacterial lifestyles. It controls a multitude of processes including production of extracellular polysaccharide ...
Cyclic dimeric GMP (c-di-GMP) has emerged as a key regulatory player in the transition between planktonic and sedentary biofilm-associated bacterial lifestyles. It controls a multitude of processes including production of extracellular polysaccharides (EPSs). The PilZ domain, consisting of an N-terminal "RxxxR" motif and a β-barrel domain, represents a prototype c-di-GMP receptor. We identified a class of c-di-GMP-responsive proteins, represented by the AraC-like transcription factor CuxR in plant symbiotic α-proteobacteria. In Sinorhizobium meliloti, CuxR stimulates transcription of an EPS biosynthesis gene cluster at elevated c-di-GMP levels. CuxR consists of a Cupin domain, a helical hairpin, and bipartite helix-turn-helix motif. Although unrelated in sequence, the mode of c-di-GMP binding to CuxR is highly reminiscent to that of PilZ domains. c-di-GMP interacts with a conserved N-terminal RxxxR motif and the Cupin domain, thereby promoting CuxR dimerization and DNA binding. We unravel structure and mechanism of a previously unrecognized c-di-GMP-responsive transcription factor and provide insights into the molecular evolution of c-di-GMP binding to proteins.
LOEWE Center for Synthetic Microbiology, Philipps-Universität Marburg, 35043 Marburg, Germany.