Mur, a manganese-responsive, Fur-like regulator in Rhizobium leguminosarum

Diaz-Mireles, Edith (2005) Mur, a manganese-responsive, Fur-like regulator in Rhizobium leguminosarum. Doctoral thesis, University of East Anglia.

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Abstract

The Ferric uptake regulator (Fur) is widely distributed in bacteria and in many species ( e.g. E. coli) it plays an essential role in the regulation of several genes involved in iron acquisition. Fur binds to the regulatory DNA of these genes through a conserved cis-sequence known as the fur-box. Interestingly, a Fur homologue was identified in R. leguminosarum, which did not regulate any of the expected iron-responsive genes. However, mutations in this gene severely affected the expression of the sitABCD operon, which was initially thought to be involved in iron transport. but. in this project it was demonstrated that this operon is involved in the transport of manganese. Another protein that may be involved in manganese transport was identified (MntH) and its promoter cloned. The expression of both promoters (sit and mntH) was repressed by the R. leguminosarum Fur. It was therefore decided to renamed R. leguminosarum Fur as R. leguminosarum Mur (manganese uptake regulator). This is the first Fur homologue identified as a Mn regulator in vivo. Interestingly, Mur is still responsive to iron, since it can bind to a classical /i1r-box if this is artificially supplied. Additionally, Mur can partially correct an £. coli fur-mutant. Importantly no fur-box was identified in the promoter of the sitABCD operon or mntH. However Mur does bind to the promoter of the sitABCD operon, which strongly suggests that it recognizes a new cis-sequence in addition to the canonical fur-box.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science
Depositing User:	Chris White
Date Deposited:	19 Aug 2026 08:32
Last Modified:	19 Aug 2026 08:32
URI:	https://ueaeprints.uea.ac.uk/id/eprint/104231
DOI:

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