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RsaM: a transcriptional regulator of B urkholderia spp. with novel fold
Author(s) -
Michalska Karolina,
Chhor Gekleng,
Clancy Shonda,
Jedrzejczak Robert,
Babnigg Gyorgy,
Winans Stephen C.,
Joachimiak Andrzej
Publication year - 2014
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.12868
Subject(s) - burkholderia cenocepacia , quorum sensing , biology , gene , regulator , transcription factor , genetics , transcriptional regulation , microbiology and biotechnology , virulence
B urkholderia cepacia complex is a set of closely related bacterial species that are notorious pathogens of cystic fibrosis patients, responsible for life‐threatening lung infections. Expression of several virulence factors of B urkholderia cepacia complex is controlled by a mechanism known as quorum sensing ( QS ). QS is a means of bacterial communication used to coordinate gene expression in a cell‐density‐dependent manner. The system involves the production of diffusible signaling molecules ( N ‐acyl‐ l ‐homoserine lactones, AHL s), that bind to cognate transcriptional regulators and influence their ability to regulate gene expression. One such system that is highly conserved in B urkholderia cepacia complex consists of CepI and CepR. CepI is AHL synthase, whereas CepR is an AHL ‐dependent transcription factor. In most members of the B urkholderia cepacia complex group, the cepI and cepR genes are divergently transcribed and separated by additional genes. One of them, bcam1869 , encodes the Bc RsaM protein, which was recently postulated to modulate the abundance or activity of CepI or CepR. Here, we show the crystal structure of Bc RsaM from B. cenocepacia J2315. It is a single‐domain protein with unique topology and presents a novel fold. The protein is a dimer in the crystal and in solution. This regulator has no known DNA ‐binding motifs and direct binding of Bc RsaM to the cepI promoter could not be detected in in vitro assays. Therefore, we propose that the modulatory action of RsaM might result from interactions with other components of the QS machinery rather than from direct association with the DNA promoter. Database The atomic coordinates and structure factors have been deposited in the Protein Data Bank under entry 4O2H . Structured digital abstractBcRsaM and BcRsaM bind by x-ray crystallography ( View interaction ) BcRsaM and BcRsaM bind by molecular sieving ( View interaction )