Functional domains of the Escherichia coli ferric uptake regulator protein (Fur).
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.
Stojiljkovic
I
I
Mikrobiologie/Membranphysiologie, Auf der Morgenstelle, Tübingen, Germany.
Hantke
K
K
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D017931:DNA Primers; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial