Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
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Drug
Enzyme
Compound
Query: KEGG:D02011 (
FAD
)
5,530
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Flavodoxins (Flds) are small, bacterial proteins that transfer electrons to various redox enzymes. Flavodoxins are reduced by ferredoxin/flavodoxin NADP
+
oxidoreductases (FNRs), but little is known of the FNR-Fld interaction. Here, we compare the interactions of two flavodoxins (Fld1-2), one flavodoxin-like protein (NrdI), and three different thioredoxin reductase (TrxR)-like FNRs (
FNR1
-3), all from Bacillus cereus. Steady-state kinetics shows that the FNR2-Fld2 electron transfer pair is particularly efficient, and redox potential measurements also indicate that this is the most favorable electron donor/acceptor pair. Furthermore, crystal structures of
FNR1
and FNR2 show that the proteins have crystallized in different conformations, a closed and an open conformation, respectively. We suggest that a large-scale conformational rearrangement takes place during the FNR catalytic cycle to allow for the binding and reduction of the Fld and, subsequently, the re-reduction of the FNR by NADPH. Finally, inspection of the residues surrounding the
FAD
cofactor in the FNR active site shows that a key isoalloxazine ring-stacking residue is different in
FNR1
and FNR2, which could explain the large difference in catalytic efficiency between the two FNRs. To date, all of the characterized TrxR-like FNRs have a residue with aromatic character stacking against the
FAD
isoalloxazine ring, and this has been thought to be a conserved feature of this class of FNRs.
FNR1
, however, has a valine in this position. Bioinformatic analysis shows that the TrxR-like FNRs can actually be divided into two groups, one group where the
FAD
-stacking residue has aromatic character and another group where it is valine.
...
PMID:The Characterization of Different Flavodoxin Reductase-Flavodoxin (FNR-Fld) Interactions Reveals an Efficient FNR-Fld Redox Pair and Identifies a Novel FNR Subclass. 3014 64
