4Q7E

Non-phosphorylated HemR Receiver Domain from Leptospira biflexa

Summary for 4Q7E

• Entry DOI: 10.2210/pdb4q7e/pdb
• Descriptor: Response regulator of a two component regulatory system, GLYCEROL, SULFATE ION, ... (4 entities in total)
• Functional Keywords: response regulator, dna binding protein, signaling protein
• Biological source: Leptospira biflexa serovar Patoc
• Total number of polymer chains: 2
• Total formula weight: 30270.58

Authors

Morero, N.R.,Buschiazzo, A. (deposition date: 2014-04-24, release date: 2014-05-14, Last modification date: 2024-02-28)

Primary citation

Morero, N.R.,Botti, H.,Nitta, K.R.,Carrion, F.,Obal, G.,Picardeau, M.,Buschiazzo, A.
HemR is an OmpR/PhoB-like response regulator from Leptospira, which simultaneously effects transcriptional activation and repression of key haem metabolism genes.
Mol.Microbiol., 94:340-352, 2014

PubMed Abstract: Several Leptospira species cause leptospirosis, the most extended zoonosis worldwide. In bacteria, two-component systems constitute key signalling pathways, some of which are involved in pathogenesis. The physiological roles of two-component systems in Leptospira are largely unknown, despite identifying several dozens within their genomes. Biochemical confirmation of an operative phosphorelaying two-component system has been obtained so far only for the Hklep/Rrlep pair. It is known that hklep/rrlep knockout strains of Leptospira biflexa result in haem auxotrophy, although their de novo biosynthesis machinery remains fully functional. Haem is essential for Leptospira, but information about Hklep/Rrlep effector function(s) and target(s) is still lacking. We are now reporting a thorough molecular characterization of this system, which we rename HemK/HemR. The DNA HemR-binding motif was determined, and found within the genomes of saprophyte and pathogenic Leptospira. In this way, putative HemR-regulated genes were pinpointed, including haem catabolism-related (hmuO - haem oxygenase) and biosynthesis-related (the hemA/C/D/B/L/E/N/G operon). Specific HemR binding to these two promoters was quantified, and a dual function was observed in vivo, inversely repressing the hmuO, while activating the hemA operon transcription. The crystal structure of HemR receiver domain was determined, leading to a mechanistic model for its dual regulatory role.

PubMed: 25145397
DOI: 10.1111/mmi.12763

Experimental method

X-RAY DIFFRACTION (1.441 Å)