ID   ISF_METTE               Reviewed;         191 AA.
AC   Q50562;
DT   29-APR-2008, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-1998, sequence version 2.
DT   03-AUG-2022, entry version 50.
DE   RecName: Full=Iron-sulfur flavoprotein;
DE            Short=Isf;
GN   Name=isf;
OS   Methanosarcina thermophila.
OC   Archaea; Euryarchaeota; Stenosarchaea group; Methanomicrobia;
OC   Methanosarcinales; Methanosarcinaceae; Methanosarcina.
OX   NCBI_TaxID=2210;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], PROTEIN SEQUENCE OF 1-5, FMN BINDING,
RP   IRON-SULFUR CLUSTER, AND SUBUNIT.
RC   STRAIN=ATCC 43570 / DSM 1825 / OCM 12 / TM-1;
RX   PubMed=8798638; DOI=10.1074/jbc.271.39.24023;
RA   Latimer M.T., Painter M.H., Ferry J.G.;
RT   "Characterization of an iron-sulfur flavoprotein from Methanosarcina
RT   thermophila.";
RL   J. Biol. Chem. 271:24023-24028(1996).
RN   [2]
RP   FUNCTION.
RX   PubMed=9756881; DOI=10.1074/jbc.273.41.26462;
RA   Becker D.F., Leartsakulpanich U., Surerus K.K., Ferry J.G., Ragsdale S.W.;
RT   "Electrochemical and spectroscopic properties of the iron-sulfur
RT   flavoprotein from Methanosarcina thermophila.";
RL   J. Biol. Chem. 273:26462-26469(1998).
RN   [3]
RP   IRON-SULFUR CLUSTER BINDING AT CYS-47; CYS-50; CYS-53 AND CYS-59, AND
RP   MUTAGENESIS OF CYS-16; CYS-47; CYS-50; CYS-53; CYS-59 AND CYS-179.
RX   PubMed=10986231; DOI=10.1128/jb.182.19.5309-5316.2000;
RA   Leartsakulpanich U., Antonkine M.L., Ferry J.G.;
RT   "Site-specific mutational analysis of a novel cysteine motif proposed to
RT   ligate the 4Fe-4S cluster in the iron-sulfur flavoprotein of the
RT   thermophilic methanoarchaeon Methanosarcina thermophila.";
RL   J. Bacteriol. 182:5309-5316(2000).
CC   -!- FUNCTION: Redox-active protein probably involved in electron transport
CC       during fermentation of acetate to methane.
CC       {ECO:0000269|PubMed:9756881}.
CC   -!- COFACTOR:
CC       Name=FMN; Xref=ChEBI:CHEBI:58210;
CC       Note=Binds 1 FMN per subunit.;
CC   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883;
CC       Note=Binds 1 [4Fe-4S] cluster per subunit.;
CC   -!- SUBUNIT: Homodimer. {ECO:0000269|PubMed:8798638}.
CC   -!- MISCELLANEOUS: The electrons derived from oxidation of the carbonyl
CC       group of acetate flow from ferredoxin to the 4Fe-4S cluster and then to
CC       the FMN cofactor.
CC   -!- SIMILARITY: Belongs to the SsuE family. Isf subfamily. {ECO:0000305}.
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DR   EMBL; U50189; AAC45465.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q50562; -.
DR   SMR; Q50562; -.
DR   GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IEA:UniProtKB-KW.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0016491; F:oxidoreductase activity; IEA:InterPro.
DR   Gene3D; 3.40.50.360; -; 1.
DR   InterPro; IPR029039; Flavoprotein-like_sf.
DR   InterPro; IPR005025; FMN_Rdtase-like.
DR   Pfam; PF03358; FMN_red; 1.
DR   SUPFAM; SSF52218; SSF52218; 1.
PE   1: Evidence at protein level;
KW   4Fe-4S; Direct protein sequencing; Flavoprotein; FMN; Iron; Iron-sulfur;
KW   Metal-binding.
FT   CHAIN           1..191
FT                   /note="Iron-sulfur flavoprotein"
FT                   /id="PRO_0000332945"
FT   BINDING         47
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT   BINDING         50
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT   BINDING         53
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT   BINDING         59
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT   MUTAGEN         16
FT                   /note="C->S: Unmodified 4Fe-4S-cluster properties in
FT                   electron paramagnetic resonance."
FT                   /evidence="ECO:0000269|PubMed:10986231"
FT   MUTAGEN         47
FT                   /note="C->S: Modified 4Fe-4S-cluster properties in electron
FT                   paramagnetic resonance."
FT                   /evidence="ECO:0000269|PubMed:10986231"
FT   MUTAGEN         50
FT                   /note="C->A: Formation of a 3Fe-4S cluster in place of the
FT                   4Fe-4S cluster."
FT                   /evidence="ECO:0000269|PubMed:10986231"
FT   MUTAGEN         53
FT                   /note="C->S: Modified 4Fe-4S-cluster properties in electron
FT                   paramagnetic resonance."
FT                   /evidence="ECO:0000269|PubMed:10986231"
FT   MUTAGEN         59
FT                   /note="C->A: Formation of a 3Fe-4S cluster in place of the
FT                   4Fe-4S cluster."
FT                   /evidence="ECO:0000269|PubMed:10986231"
FT   MUTAGEN         179
FT                   /note="C->S: Unmodified 4Fe-4S-cluster properties in
FT                   electron paramagnetic resonance."
FT                   /evidence="ECO:0000269|PubMed:10986231"
SQ   SEQUENCE   191 AA;  20921 MW;  0244D6DE7CF9AFAC CRC64;
     MKITGISGSP RKGQNCEKII GAALEVAKER GFETDTVFIS NEEVAPCKAC GACRDQDFCV
     IDDDMDEIYE KMRAADGIIV AAPVYMGNYP AQLKALFDRS VLLRRKNFAL KNKVGAALSV
     GGSRNGGQEK TIQSIHDWMH IHGMIVVGDN SHFGGITWNP AEEDTVGMQT VSETAKKLCD
     VLELIQKNRD K