YfhJ, a molecular adaptor in iron-sulfur cluster formation or a frataxin-like protein?
The yfhJ gene is part of the isc operon, which encodes the machinery devoted to assemble iron-sulfur clusters in prokaryotes. Its transcript is a small acidic protein that binds the desulfurase IscS, which is essential in iron-specific metabolic pathways. To understand its cellular role, we have characterized the structure of YfhJ in solution and its interactions with potential cellular partners. It contains a modified winged helix motif, usually present in DNA binding proteins, and is able to bind iron cations. The IscS interaction surface is the same as that involved in iron binding. This observation and the pattern of conservation through species strongly suggest that YfhJ is a molecular adaptor that is able to modulate the function of IscS in iron-sulfur cluster formation. The remarkable similarity between the in vitro behavior of YfhJ and that of the protein frataxin also suggests new hypotheses regarding the functional role of both proteins.
Pastore
Chiara
C
National Institute for Medical Research, The Ridgeway, London NW7 1AA, United Kingdom. apastor@nimr.mrc.ac.uk
Adinolfi
Salvatore
S
Huynen
Martjin A
MA
Rybin
Vladimir
V
Martin
Stephen
S
Mayer
Mathias
M
Bukau
Bernd
B
Pastore
Annalisa
A
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D033862:Iron-Binding Proteins / Q000737:chemistry; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D011487:Protein Conformation; D000096923:Frataxin
D001426:Bacterial Proteins; D007501:Iron; D033862:Iron-Binding Proteins; D007506:Iron-Sulfur Proteins; D000096923:Frataxin