Functional domains of the Escherichia coli ferric uptake regulator protein (Fur)

Mol Gen Genet. 1995 Apr 20;247(2):199-205. doi: 10.1007/BF00705650.


The functions of N- and C-terminal domains of the Fur repressor of Escherichia coli in promoter recognition and dimerization were studied. We investigated the ability of fusion proteins containing the N- or C-terminal domain of Fur to dimerize and to repress a Fur-regulated lacZ fusion gene. The N-terminal domain, when fused to the C-terminal domain of the repressor CI857, repressed a Fur-regulated lacZ fusion. However, the Fur-CI857 fusion was unable to complement the growth defect of an E. coli fur mutant on fumarate and succinate. The C-terminal domain of Fur, when fused to the N-terminus of CI857, repressed a lambda Pr-regulated lacZ fusion, indicating dimerization of the chimeric protein, which is a prerequisite for CI activity. Both fusion proteins were fully active under both iron-rich and iron-poor growth conditions. We conclude that the N-terminal domain of Fur is involved in recognition of the Fur-responsive promoter and the C-terminus mediates oligomerization of the repressor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • DNA Primers
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Molecular Sequence Data
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Repressor Proteins / genetics*
  • Repressor Proteins / metabolism


  • Bacterial Proteins
  • DNA Primers
  • Recombinant Fusion Proteins
  • Repressor Proteins
  • ferric uptake regulating proteins, bacterial