PMID- 11525168
OWN - NLM
STAT- MEDLINE
DCOM- 20011204
LR  - 20131121
IS  - 0969-2126 (Print)
IS  - 0969-2126 (Linking)
VI  - 9
IP  - 4
DP  - 2001 Apr 4
TI  - Crystal structures of a novel ferric reductase from the hyperthermophilic
      archaeon Archaeoglobus fulgidus and its complex with NADP+.
PG  - 311-9
AB  - BACKGROUND: Studies performed within the last decade have indicated that
      microbial reduction of Fe(III) to Fe(II) is a biologically significant process.
      The ferric reductase (FeR) from Archaeoglobus fulgidus is the first reported
      archaeal ferric reductase and it catalyzes the flavin-mediated reduction of
      ferric iron complexes using NAD(P)H as the electron donor. Based on its catalytic
      activity, the A. fulgidus FeR resembles the bacterial and eukaryotic assimilatory
      type of ferric reductases. However, the high cellular abundance of the A.
      fulgidus FeR (approximately 0.75% of the total soluble protein) suggests a
      catabolic role for this enzyme as the terminal electron acceptor in a ferric
      iron-based respiratory pathway [1]. RESULTS: The crystal structure of recombinant
      A. fulgidus FeR containing a bound FMN has been solved at 1.5 A resolution by
      multiple isomorphous replacement/ anomalous diffraction (MIRAS) phasing methods, 
      and the NADP+- bound complex of FeR was subsequently determined at 1.65 A
      resolution. FeR consists of a dimer of two identical subunits, although only one 
      subunit has been observed to bind the redox cofactors. Each subunit is organized 
      around a six-stranded antiparallel beta barrel that is homologous to the FMN
      binding protein from Desulfovibrio vulgaris. This fold has been shown to be
      related to a circularly permuted version of the flavin binding domain of the
      ferredoxin reductase superfamily. The A. fulgidus ferric reductase is further
      distinguished from the ferredoxin reductase superfamily by the absence of a
      Rossmann fold domain that is used to bind the NAD(P)H. Instead, FeR uses its
      single domain to provide both the flavin and the NAD(P)H binding sites. Potential
      binding sites for ferric iron complexes are identified near the cofactor binding 
      sites. CONCLUSIONS: The work described here details the structures of the
      enzyme-FMN, enzyme-FMN-NADP+, and possibly the enzyme-FMN-iron intermediates that
      are present during the reaction mechanism. This structural information helps
      identify roles for specific residues during the reduction of ferric iron
      complexes by the A. fulgidus FeR.
FAU - Chiu, H J
AU  - Chiu HJ
AD  - Division of Chemistry and Chemical Engineering, California Institute of
      Technology, 91125, USA.
FAU - Johnson, E
AU  - Johnson E
FAU - Schroder, I
AU  - Schroder I
FAU - Rees, D C
AU  - Rees DC
LA  - eng
SI  - PDB/1I0R
SI  - PDB/1I0S
GR  - GM-45162/GM/NIGMS NIH HHS/United States
GR  - HL-16251/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Structure
JT  - Structure (London, England : 1993)
JID - 101087697
RN  - 0 (Recombinant Proteins)
RN  - 0 (Solvents)
RN  - 53-59-8 (NADP)
RN  - 7N464URE7E (Flavin Mononucleotide)
RN  - E1UOL152H7 (Iron)
RN  - EC 1.5.1.38 (FMN Reductase)
RN  - EC 1.6.- (NADH, NADPH Oxidoreductases)
RN  - EC 1.6.99.- (ferric citrate iron reductase)
RN  - FXS1BY2PGL (Mercury)
SB  - IM
MH  - Archaeoglobus fulgidus/*enzymology
MH  - Binding Sites
MH  - Catalysis
MH  - Crystallography, X-Ray
MH  - Dimerization
MH  - Enzyme Stability
MH  - *FMN Reductase
MH  - Flavin Mononucleotide/metabolism
MH  - Iron/metabolism
MH  - Mercury/metabolism
MH  - Models, Molecular
MH  - NADH, NADPH Oxidoreductases/*chemistry/*metabolism
MH  - NADP/*metabolism
MH  - Oxidation-Reduction
MH  - Protein Binding
MH  - Protein Conformation
MH  - Recombinant Proteins/chemistry/metabolism
MH  - Solvents
MH  - Static Electricity
MH  - Temperature
EDAT- 2001/08/30 10:00
MHDA- 2002/01/05 10:01
CRDT- 2001/08/30 10:00
PHST- 2001/08/30 10:00 [pubmed]
PHST- 2002/01/05 10:01 [medline]
PHST- 2001/08/30 10:00 [entrez]
AID - S0969212601005895 [pii]
PST - ppublish
SO  - Structure. 2001 Apr 4;9(4):311-9.