Literature summary for 1.15.1.2 extracted from

Sheng, Y.; Abreu, I.; Cabelli, D.; Maroney, M.; Miller, A.; Teixeira, M.; Valentine, J.
Superoxide dismutases and superoxide reductases (2014), Chem. Rev., 114, 3854-3918 .

Crystallization (Commentary)

Crystallization (Comment)	Organism
crystal structure determination at 1.55 A resolution, PDB ID 1Y07	Treponema pallidum
crystal structure determination at 1.9 A resolution, PDB ID 1DFX	Desulfovibrio desulfuricans
crystal structure determination at 2.0 A and 1.1 A resolution, respectively, PDB IDs 2AMU and 3QZB	Thermotoga maritima
crystal structure determination at 2.0 A and 1.7 A resolution, respectively, PDB IDs 1DO6 and 1DQI	Pyrococcus furiosus
crystal structure determination at 2.5 A resolution, PDB ID 2HVB	Pyrococcus horikoshii
crystal structures determination of wild/tzp and mutant enzymes at 1.15-1.95 A resolution, PDB IDs 1VZI, 1VZG, 1VZH, 2JI1, 2JI2, and 2JI3	Desulfarculus baarsii

Protein Variants

Protein Variants	Comment	Organism
E114A	site-directed mutagenesis, crystal structure determination	Desulfarculus baarsii
E12Q	site-directed mutagenesis	Archaeoglobus fulgidus
E12V	site-directed mutagenesis	Archaeoglobus fulgidus
E23A	site-directed mutagenesis	Ignicoccus hospitalis
E46A	site-directed mutagenesis, crystal structure determination	Desulfarculus baarsii
E47A	site-directed mutagenesis	Desulfovibrio desulfuricans
E47A	site-directed mutagenesis	Desulfovibrio vulgaris
E47A	site-directed mutagenesis, crystal structure determination	Desulfarculus baarsii
E48A	site-directed mutagenesis	Desulfovibrio desulfuricans
E48A	site-directed mutagenesis	Desulfovibrio vulgaris
E48A	site-directed mutagenesis	Treponema pallidum
K48I	site-directed mutagenesis	Desulfarculus baarsii
T24K	site-directed mutagenesis	Ignicoccus hospitalis

Metals/Ions

Metals/Ions	Comment	Organism
Fe2+	catalytic Fe2+ binding residues are H10, H35, H41, C97, and H100. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Nanoarchaeum equitans
Fe2+	catalytic Fe2+ binding residues are H14, H40, H46, C110, and H113. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Archaeoglobus fulgidus
Fe2+	catalytic Fe2+ binding residues are H16, H41, H47, C111, and H114. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Pyrococcus furiosus
Fe2+	catalytic Fe2+ binding residues are H16, H41, H47, C111, and H114. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Archaeoglobus fulgidus
Fe2+	catalytic Fe2+ binding residues are H17, H45, H51, C115, and H118. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Dosidicus gigas
Fe2+	catalytic Fe2+ binding residues are H17, H45, H51, C115, and H118. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Thermotoga maritima
Fe2+	catalytic Fe2+ binding residues are H25, H50, H56, C109, and H112. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Ignicoccus hospitalis
Fe2+	catalytic Fe2+ binding residues are H25, H50, H56, C111, and H114. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Pyrococcus horikoshii
Fe2+	catalytic Fe2+ binding residues are H49, H69, H74, C115, and H118. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Desulfovibrio desulfuricans
Fe2+	catalytic Fe2+ binding residues are H49, H69, H74, C115, and H118. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Desulfovibrio vulgaris
Fe2+	catalytic Fe2+ binding residues are H49, H69, H74, C115, and H118. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Desulfarculus baarsii
Fe2+	catalytic Fe2+ binding residues are H50, H70, H76, C119, and H122. With the exception of the class IV (methanoferrodoxins) and the atypical SORs, they all appear to contain one or two iron centers: the catalytic center plus the desulforedoxin-like and rubredoxin-like, Dx/Rb-like, center	Treponema pallidum

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.
superoxide + reduced acceptor + 2 H+	Desulfovibrio desulfuricans	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Desulfovibrio vulgaris	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Archaeoglobus fulgidus	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Dosidicus gigas	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Pyrococcus furiosus	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Desulfarculus baarsii	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Thermotoga maritima	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Pyrococcus horikoshii	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Nanoarchaeum equitans	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Ignicoccus hospitalis	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Treponema pallidum	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Archaeoglobus fulgidus ATCC 49558	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Ignicoccus hospitalis KIN4/I / DSM 18386 / JCM 14125	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Pyrococcus furiosus ATCC 43587	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Desulfarculus baarsii ATCC 33931	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Thermotoga maritima ATCC 43589	-	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	Treponema pallidum Nichols	-	H2O2 + oxidized acceptor	-	?

Organism

Organism	UniProt	Comment	Textmining
Archaeoglobus fulgidus	-	-	-
Archaeoglobus fulgidus	O29903	-	-
Archaeoglobus fulgidus ATCC 49558	O29903	-	-
Desulfarculus baarsii	Q46495	-	-
Desulfarculus baarsii ATCC 33931	Q46495	-	-
Desulfovibrio desulfuricans	-	-	-
Desulfovibrio vulgaris	-	-	-
Dosidicus gigas	-	-	-
Ignicoccus hospitalis	A8AC72	-	-
Ignicoccus hospitalis KIN4/I / DSM 18386 / JCM 14125	A8AC72	-	-
Nanoarchaeum equitans	Q74MF3	-	-
Pyrococcus furiosus	P82385	-	-
Pyrococcus furiosus ATCC 43587	P82385	-	-
Pyrococcus horikoshii	O58810	-	-
Thermotoga maritima	Q9WZC6	-	-
Thermotoga maritima ATCC 43589	Q9WZC6	-	-
Treponema pallidum	O82795	-	-
Treponema pallidum Nichols	O82795	-	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.
superoxide + reduced acceptor + 2 H+	-	Desulfovibrio desulfuricans	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Desulfovibrio vulgaris	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Archaeoglobus fulgidus	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Dosidicus gigas	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Pyrococcus furiosus	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Desulfarculus baarsii	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Thermotoga maritima	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Pyrococcus horikoshii	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Nanoarchaeum equitans	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Ignicoccus hospitalis	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Treponema pallidum	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Archaeoglobus fulgidus ATCC 49558	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Ignicoccus hospitalis KIN4/I / DSM 18386 / JCM 14125	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Pyrococcus furiosus ATCC 43587	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Desulfarculus baarsii ATCC 33931	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Thermotoga maritima ATCC 43589	H2O2 + oxidized acceptor	-	?
superoxide + reduced acceptor + 2 H+	-	Treponema pallidum Nichols	H2O2 + oxidized acceptor	-	?

Subunits

Subunits	Comment	Organism
dimer	-	Desulfovibrio desulfuricans
dimer	-	Desulfarculus baarsii
dimer	-	Treponema pallidum
tetramer	-	Pyrococcus furiosus
tetramer	-	Thermotoga maritima
tetramer	-	Pyrococcus horikoshii

Synonyms

Synonyms	Comment	Organism
1Fe-SOR	-	Archaeoglobus fulgidus
1Fe-SOR	-	Dosidicus gigas
1Fe-SOR	-	Pyrococcus furiosus
1Fe-SOR	-	Thermotoga maritima
1Fe-SOR	-	Pyrococcus horikoshii
1Fe-SOR	-	Nanoarchaeum equitans
1Fe-SOR	-	Ignicoccus hospitalis
1Fe-SOR	-	Treponema pallidum
2Fe-SOR	-	Desulfovibrio desulfuricans
2Fe-SOR	-	Desulfovibrio vulgaris
2Fe-SOR	-	Archaeoglobus fulgidus
2Fe-SOR	-	Desulfarculus baarsii
class I SOR	-	Desulfovibrio desulfuricans
class I SOR	-	Desulfovibrio vulgaris
class I SOR	-	Archaeoglobus fulgidus
class I SOR	-	Desulfarculus baarsii
class II SOR	-	Archaeoglobus fulgidus
class II SOR	-	Dosidicus gigas
class II SOR	-	Pyrococcus furiosus
class II SOR	-	Thermotoga maritima
class II SOR	-	Pyrococcus horikoshii
class II SOR	-	Nanoarchaeum equitans
class II SOR	-	Ignicoccus hospitalis
class II SOR	-	Treponema pallidum
SOR	-	Desulfovibrio desulfuricans
SOR	-	Desulfovibrio vulgaris
SOR	-	Archaeoglobus fulgidus
SOR	-	Dosidicus gigas
SOR	-	Pyrococcus furiosus
SOR	-	Desulfarculus baarsii
SOR	-	Thermotoga maritima
SOR	-	Pyrococcus horikoshii
SOR	-	Nanoarchaeum equitans
SOR	-	Ignicoccus hospitalis
SOR	-	Treponema pallidum

General Information

General Information	Comment	Organism
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Desulfovibrio desulfuricans
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Desulfovibrio vulgaris
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Archaeoglobus fulgidus
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Dosidicus gigas
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Pyrococcus furiosus
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Desulfarculus baarsii
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Thermotoga maritima
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Pyrococcus horikoshii
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Nanoarchaeum equitans
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Ignicoccus hospitalis
evolution	Fe-SOR classification, detailed overview. One classification takes into consideration the primary and tertiary structures of SORs some enzymes contain only one Fe ion, but have a longer N-terminus with amino acid sequence and structural similarities with those of the respective domain of desulfoferrodoxins, but lacking the cysteine ligands to the desulforedoxin (Dfxs)-like center. According to the authors, SORs fall into three classes: classes I (Dfxs), II (neelaredoxins), and III (neelaredoxins structurally homologous to desulfoferrodoxins, with only one Fe center). In dendograms constructed from available amino acid sequences, class III enzymes cluster within the class I enzymes, it is plausible that class III SORs evolved from class I proteins by loss of the cysteine residues binding the desulforedoxin-like center, an event that may have occurred more than once because the Dfxs are not monophyletic. This classification misses the family of methanoferrodoxins. Another classification is based on the variability of N-terminal domains classifying SORs into seven classes. Class I or Dx-SOR includes the 2Fe-SORs, where the N-terminal is a desulforedoxin-like (Dx) domain. Class II includes the 1Fe-SORs that have no extra N-terminal domain. Class III SORs are analogous to Dx-SORs but lacking some or all of the Fe cysteine ligands (FeCys4) for the desulforedoxin-like Fe center and therefore lacking the FeCy4 site. Class IV includes SORs with an extra C-terminal domain containing an iron-sulfur center. The fifth class, termed HTH-Dx-SOR, includes Dx-SORs (2Fe-SOR) with an extended N-terminal helix-turn-helix domain present in transcription regulators. The sixth class, termed TAT-SOR, includes SORs from only a few organisms and the sequences are preceded by a putative twin-arginine signal peptide that suggests their periplasmic localization	Treponema pallidum
additional information	key catalytic residue is E23, catalytic Fe2+ binding residues are H25, H50, H56, C109, and H112	Ignicoccus hospitalis
additional information	key catalytic residue is K9, catalytic Fe2+ binding residues are H10, H35, H41, C97, and H100	Nanoarchaeum equitans
additional information	key catalytic residues are E12 and K13, catalytic Fe2+ binding residues are H14, H40, H46, C110, and H113	Archaeoglobus fulgidus
additional information	key catalytic residues are E14 and K15, catalytic Fe2+ binding residues are H16, H41, H47, C111, and H114	Pyrococcus furiosus
additional information	key catalytic residues are E14 and K15, catalytic Fe2+ binding residues are H16, H41, H47, C111, and H114	Archaeoglobus fulgidus
additional information	key catalytic residues are E15 and K16, catalytic Fe2+ binding residues are H17, H45, H51, C115, and H118	Dosidicus gigas
additional information	key catalytic residues are E15 and K16, catalytic Fe2+ binding residues are H17, H45, H51, C115, and H118	Thermotoga maritima
additional information	key catalytic residues are E23, K24, H25, H50, H56, C111, and H114	Pyrococcus horikoshii
additional information	key catalytic residues are E47 and K48, catalytic Fe2+ binding residues are H49, H69, H74, C115, and H118	Desulfovibrio desulfuricans
additional information	key catalytic residues are E47 and K48, catalytic Fe2+ binding residues are H49, H69, H74, C115, and H118	Desulfovibrio vulgaris
additional information	key catalytic residues are E47 and K48, catalytic Fe2+ binding residues are H49, H69, H74, C115, and H118	Desulfarculus baarsii
additional information	key catalytic residues are E48, K40, H50, H70, H76, C119, and H122	Treponema pallidum