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A new small regulatory protein, HmuP, modulates haemin acquisition in Sinorhizobium meliloti

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 demonst...

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Autores principales: Amarelle, Vanesa, Koziol, Uriel, Rosconi, Federico, Noya, Francisco, O'Brian, Mark R., Fabiano, Elena
Formato: Texto
Lenguaje:English
Publicado: Microbiology Society 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068671/
https://www.ncbi.nlm.nih.gov/pubmed/20167620
http://dx.doi.org/10.1099/mic.0.037713-0
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author Amarelle, Vanesa
Koziol, Uriel
Rosconi, Federico
Noya, Francisco
O'Brian, Mark R.
Fabiano, Elena
author_facet Amarelle, Vanesa
Koziol, Uriel
Rosconi, Federico
Noya, Francisco
O'Brian, Mark R.
Fabiano, Elena
author_sort Amarelle, Vanesa
collection PubMed
description 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 β-sheets are well conserved. Our data indicate that at least one of the β-sheets is important for HmuP activity.
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spelling pubmed-30686712011-06-13 A new small regulatory protein, HmuP, modulates haemin acquisition in Sinorhizobium meliloti Amarelle, Vanesa Koziol, Uriel Rosconi, Federico Noya, Francisco O'Brian, Mark R. Fabiano, Elena Microbiology (Reading) Physiology and Biochemistry 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 β-sheets are well conserved. Our data indicate that at least one of the β-sheets is important for HmuP activity. Microbiology Society 2010-06 /pmc/articles/PMC3068671/ /pubmed/20167620 http://dx.doi.org/10.1099/mic.0.037713-0 Text en Copyright © 2010, SGM
spellingShingle Physiology and Biochemistry
Amarelle, Vanesa
Koziol, Uriel
Rosconi, Federico
Noya, Francisco
O'Brian, Mark R.
Fabiano, Elena
A new small regulatory protein, HmuP, modulates haemin acquisition in Sinorhizobium meliloti
title A new small regulatory protein, HmuP, modulates haemin acquisition in Sinorhizobium meliloti
title_full A new small regulatory protein, HmuP, modulates haemin acquisition in Sinorhizobium meliloti
title_fullStr A new small regulatory protein, HmuP, modulates haemin acquisition in Sinorhizobium meliloti
title_full_unstemmed A new small regulatory protein, HmuP, modulates haemin acquisition in Sinorhizobium meliloti
title_short A new small regulatory protein, HmuP, modulates haemin acquisition in Sinorhizobium meliloti
title_sort new small regulatory protein, hmup, modulates haemin acquisition in sinorhizobium meliloti
topic Physiology and Biochemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068671/
https://www.ncbi.nlm.nih.gov/pubmed/20167620
http://dx.doi.org/10.1099/mic.0.037713-0
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