Skip to main content
padlock icon - secure page this page is secure

Free Content The mntH gene encodes the major Mn2+ transporter in Bradyrhizobium japonicum and is regulated by manganese via the Fur protein

Download Article:
 Download
(PDF)
 
Summary

The bacterial Nramp family protein MntH is a divalent metal transporter, but mntH mutants have little or no phenotype in organisms where it has been studied. Here, we identify the mntH homologue of Bradyrhizobium japonicum, and demonstrate that it is essential for Mn2+ transport and for maintenance of cellular manganese homeostasis. Transport activity was induced under manganese deficiency, and Fe2+ did not compete with 54Mn2+ for uptake by cells. The steady-state level of mntH mRNA was negatively regulated by manganese, but was unaffected by iron. Control of mntH expression and Mn2+ transport by manganese was lost in a fur strain, resulting in constitutively high activity. Fur protected a 35 bp region of the mntH promoter in DNase I footprinting analysis that includes three imperfect direct repeat hexamers that are needed for full occupancy. Mn2+ increased the affinity of Fur for the mntH promoter by over 50-fold, with a Kd value of 2.2 nM in the presence of metal. The findings identify MntH as the major Mn2+ transporter in B. japonicum, and show that Fur is a manganese-responsive regulator in that organism. Furthermore, Fe2+ is neither a substrate for MntH nor a regulator of mntH expression in vivo.
No References
No Citations
No Supplementary Data
No Article Media
No Metrics

Document Type: Research Article

Publication date: April 1, 2009

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more