Journal
MICROBIOLOGY-SGM
Volume 156, Issue -, Pages 1873-1882Publisher
MICROBIOLOGY SOC
DOI: 10.1099/mic.0.037713-0
Keywords
-
Categories
Funding
- NIH [R03 TW007353, GM067966]
- Programa de Desarrollo de las Ciencias Basicas (PEDECIBA)
- Comision Sectorial de Investigacion Cientifica (CSIC), Uruguay
Ask authors/readers for more resources
Sinorhizobium meliloti has multiple systems for iron acquisition, including the use of haem as an iron source. Haem internalization involves the ShmR haem outer membrane receptor and the hmuTUV locus, which participates in haem transport across the cytoplasmic membrane. Previous studies have demonstrated that expression of the shmR gene is negatively regulated by iron through RirA. Here, we identify hmuP in a genetic screen for mutants that displayed aberrant control of shmR. The normal induction of shmR in response to iron limitation was lost in the hmuP mutant, showing that this gene positively affects shmR expression. Moreover, the HmuP protein is not part of the haemin transporter system. Analysis of gene expression and siderophore production indicates that disruption of hmuP does not affect other genes related to the iron-restriction response. Our results strongly indicate that the main function of HmuP is the transcriptional regulation of shmR. Sequence alignment of HmuP homologues and comparison with the NMR structure of Rhodopseudomonas palustris CGA009 HmuP protein revealed that certain amino acids localized within predicted beta-sheets are well conserved. Our data indicate that at least one of the beta-sheets is important for HmuP activity.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available