Rieske non-heme iron oxygenase (RO) family, N-terminal Rieske domain of the oxygenase alpha subunit; The RO family comprise a large class of aromatic ring-hydroxylating dioxygenases found predominantly in microorganisms. These enzymes enable microorganisms to tolerate and even exclusively utilize aromatic compounds for growth. ROs consist of two or three components: reductase, oxygenase, and ferredoxin (in some cases) components. The oxygenase component may contain alpha and beta subunits, with the beta subunit having a purely structural function. Some oxygenase components contain only an alpha subunit. The oxygenase alpha subunit has two domains, an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from the reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis. Reduced pyridine nucleotide is used as the initial source of two electrons for dioxygen activation.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646   19 WYPICPVGFIE--DKPVSLRRLGYKLAVWRDTDGTLHALEDHCPHRGAPLSRG-VNLGDRLQCPYHGVEVRCDGVTARVP 95
Cdd:cd03469   1 WYFVGHSSELPepGDYVTLELGGEPLVLVRDRDGEVRAFHNVCPHRGARLCEGrGGNAGRLVCPYHGWTYDLDGKLVGVP 80

                        90       100       110       120
                ....*....|....*....|....*....|....*....|..
gi 9949646   96 GSPGCKL--EGSQATRFFHITEAAGAVWLYNSagnvEEAPPL 135
Cdd:cd03469  81 REEGFPGfdKEKLGLRTVPVEEWGGLIFVNLD----PDAPPL 118

pheophorbide a oxygenase

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646    19 WYPicpVGFIED----KPVSLRRLGYKLAVWRDT-DGTLHALEDHCPHRGAPLSRG-VNLGDRLQCPYHGVEVRCDGVTA 92
Cdd:PLN02518  91 WYP---VSLVEDldpsVPTPFQLLGRDLVLWKDPnQGEWVAFDDKCPHRLAPLSEGrIDENGHLQCSYHGWSFDGCGSCT 167

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646    93 RVPGS----PGCKLEGSQ---ATRFFHITeAAGAVWLYNSAGNVEEA----PPLvLPEQLTDPEFSHFLCYTEWRGDYRY 161
Cdd:PLN02518 168 RIPQAapegPEARAVKSPracAIKFPTMV-SQGLLFVWPDENGWERAqatkPPM-LPDEFDDPEFSTVTIQRDLFYGYDT 245

                        170
                 ....*....|....*
gi 9949646   162 VLDNVMDPMHGTYLH 176
Cdd:PLN02518 246 LMENVSDPSHIDFAH 260

Phenylpropionate dioxygenase or related ring-hydroxylating dioxygenase, large terminal subunit [Inorganic ion transport and metabolism, General function prediction only];

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646    8 EQLLANGLKNLWYPICPVGFIED--KPVSLRRLGYKLAVWRDTDGTLHALEDHCPHRGAPLSRGVNLGDRLQCPYHGVEV 85
Cdd:COG4638  16 ELELERIFRRGWYYVGHSSELPEpgDYLTRTILGEPVVLVRDKDGEVRAFHNVCPHRGAPLSEGRGNGGRLVCPYHGWTY 95

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646   86 RCDGVTARVPGSPGCK--LEGSQATRFFHITEAAGAVWLYNSagnvEEAPPLV-----LPEQLTD---PEFSHFLCYT-E 154
Cdd:COG4638  96 DLDGRLVGIPHMEGFPdfDPARAGLRSVPVEEWGGLIFVWLG----PDAPPLAeylgpLAEYLDPydfGELKVAGRETyE 171

                       170       180       190       200       210       220       230       240
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646  155 WRGDYRYVLDNVMDPMHGTYLHKQSHSmsegesqarfvtrdtdtgFIFekdgqrgvnfdwtewadTGMHWMrleipypkt 234
Cdd:COG4638 172 VNANWKLVVENFLDGYHVPFVHPGIIL------------------FLF-----------------PNLMIL--------- 207

                       250       260       270       280       290       300       310       320
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646  235 ggPGGNFHIVGSYTPIARDLCAVFHWRCRPltgwqRDTWRFLYRNRLEARHWAVLEQDREMLEFMEP----DANQRENL- 309
Cdd:COG4638 208 --DYPDHLVVRTVTPVSPDRTRVFVTFYVP-----KDALDPEARADLEAFWGRVFEEDREIVERQQRglrsLAYPGPYLs 280

                       330
                ....*....|....*...
gi 9949646  310 -YQHDLGLVRLRRHLKNL 326
Cdd:COG4638 281 rSPAEGGVRHFRRWLRRL 298

Rieske [2Fe-2S] domain; The rieske domain has a [2Fe-2S] centre. Two conserved cysteines coordinate one Fe ion, while the other Fe ion is coordinated by two conserved histidines. In hyperthermophilic archaea there is a SKTPCX(2-3)C motif at the C-terminus. The cysteines in this motif form a disulphide bridge, which stabilizes the protein.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646     19 WYPICPVGFI-EDKPVSLRRLGYKLAVWRDTDGTLHALEDHCPHRGAPLSRG-VNLGDRLQCPYHGVEVRCDGVTARVPG 96
Cdd:pfam00355   2 WYPVCHSSELpEGEPKVVEVGGEPLVVFRDEDGELYALEDRCPHRGAPLSEGkVNGGGRLECPYHGWRFDGTGKVVKVPA 81

Rieske non-heme iron oxygenase (RO) family, 2-Oxoquinoline 8-monooxygenase (OMO) and Carbazole 1,9a-dioxygenase (CARDO) subfamily, N-terminal Rieske domain of the oxygenase alpha subunit; ROs comprise a large class of aromatic ring-hydroxylating dioxygenases that enable microorganisms to tolerate and utilize aromatic compounds for growth. The oxygenase alpha subunit contains an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis. OMO catalyzes the NADH-dependent oxidation of the N-heterocyclic aromatic compound 2-oxoquinoline to 8-hydroxy-2-oxoquinoline, the second step in the bacterial degradation of quinoline. OMO consists of a reductase component (OMR) and an oxygenase component (OMO) that together function to shuttle electrons from the reduced pyridine nucleotide to the active site of OMO, where O2 activation and 2-oxoquinoline hydroxylation occurs. CARDO, which contains oxygenase (CARDO-O), ferredoxin (CARDO-F) and ferredoxin reductase (CARDO-R) components, catalyzes the dihydroxylation at the C1 and C9a positions of carbazole. The oxygenase component of OMO and CARDO contain only alpha subunits arranged in a trimeric structure.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646   14 GLKNLWYPICPVGFI-EDKPVSLRRLGYKLaVWRDTDGTLHALEDHCPHRGAPLSRGVNL--GDRLQCPYHGVEVRC-DG 89
Cdd:cd03548  10 GFRNHWYPALFSHELeEGEPKGIQLCGEPI-LLRRVDGKVYALKDRCLHRGVPLSKKPECftKGTITCWYHGWTYRLdDG 88

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....*.
gi 9949646   90 VTARVPGSPGCKLEGSQATRFFHITEAAGAVWLYNSAGNVEEAPPL 135
Cdd:cd03548  89 KLVTILANPDDPLIGRTGLKTYPVEEAKGMIFVFVGDGDYADPPPL 134

Tic55 is a 55kDa LLS1-related non-heme iron oxygenase associated with protein transport through the plant inner chloroplast membrane. This domain represents the N-terminal Rieske domain of the Tic55 oxygenase alpha subunit. Tic55 is closely related to the oxygenase alpha subunits of a small subfamily of enzymes found in plants as well as oxygenic cyanobacterial photosynthesizers including LLS1 (lethal leaf spot 1, also known as PaO), Ptc52, and ACD1 (accelerated cell death 1). ROs comprise a large class of aromatic ring-hydroxylating dioxygenases that enable microorganisms to tolerate and utilize aromatic compounds for growth. The oxygenase alpha subunit contains an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646   19 WYPICPV-GFIEDKPVSLRRLGYKLAVWRDTDGTLHALEDHCPHRGAPLSRGVNLGDRLQCPYHGVEVRCDGVTARVPGS 97
Cdd:cd04338  18 WYPLYLLkDVPTDAPLGLSVYDEPFVLFRDQNGQLRCLEDRCPHRLAKLSEGQLIDGKLECLYHGWQFGGEGKCVKIPQL 97

                        90       100       110
                ....*....|....*....|....*....|..
gi 9949646   98 P-GCKLEGSQATRFFHITEAAGAVWLYNSAGN 128
Cdd:cd04338  98 PaDAKIPKNACVKSYEVRDSQGVVWMWMSEAT 129

Vanillate O-demethylase oxygenase C-terminal domain; This domain is found in a wide variety of oxygenases such as Vanillate O-demethylase oxygenase and Toluene-4-sulfonate monooxygenase.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646    155 WRGDYRYVLDNVMDPMHGTYLHKQSHSMSEGE--SQARFVTRDTDTGFIFEKDG-----QRGVNFDWTEWADTGMHWMRL 227
Cdd:pfam19112   1 VDANYELIIDNLLDLSHVAFVHPGTLGGPGGAelLDARTVVEEGERSVVVTREIpgkppPPGFRAVLGDDGEVVDRWVTV 80

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646    228 EIPYP-------------KTGGPGGNFHIVGSYTPIARDLCaVFHWR-CRPLTGWQRDTWRFLYrnrlEARHWAVlEQDR 293
Cdd:pfam19112  81 EWHAPglvilligatdagAPRGPGVRLPILHAITPETETST-HYFWAlARNFDLDDADLSARLA----EANHKAF-DEDK 154

                         170       180       190       200
                  ....*....|....*....|....*....|....*....|.
gi 9949646    294 EMLEFMEP-----DANQRENLYQHDLGLVRLRRHLKNLAKA 329
Cdd:pfam19112 155 PVLEAQQRnldldDARRREVSLKADAAAVRARRILARLIEA 195

Cao (chlorophyll a oxygenase) is a rieske non-heme iron-sulfur protein located within the plastid-envelope inner and thylakoid membranes, that catalyzes the conversion of chlorophyllide a to chlorophyllide b. CAO is found not only in plants but also in chlorophytes and prochlorophytes. This domain represents the N-terminal rieske domain of the oxygenase alpha subunit. ROs comprise a large class of aromatic ring-hydroxylating dioxygenases that enable microorganisms to tolerate and utilize aromatic compounds for growth. The oxygenase alpha subunit contains an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis. Cao is closely related to several other plant RO's including Tic 55, a 55 kDa protein associated with protein transport through the inner chloroplast membrane; Ptc 52, a novel 52 kDa protein isolated from chloroplasts; and LLS1/Pao (Lethal-leaf spot 1/pheophorbide a oxygenase).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646   11 LANGLKNLWYPICPVGFIE-DKPVSLRRLGYKLAVWRDTDGTLHALEDHCPHRGAPLSRGVNLGDRLQCPYHGVEVRCDG 89
Cdd:cd04337  10 LEPGLRNFWYPVEFSKDLKmDTMVPFELFGQPWVLFRDEDGTPGCIRDECAHRACPLSLGKVIEGRIQCPYHGWEYDGDG 89

                ....*....
gi 9949646   90 VTARVPGSP 98
Cdd:cd04337  90 ECTKMPSTK 98

C-terminal catalytic domain of the oxygenase alpha subunit of dicamba O-demethylase and related aromatic ring hydroxylating dioxygenases; C-terminal catalytic domain of the oxygenase alpha subunit of Stenotrophomonas maltophilia dicamba O-demethylase (DMO) and related Rieske-type non-heme iron aromatic ring-hydroxylating oxygenases (RHOs, also known as aromatic ring hydroxylating dioxygenases). RHOs utilize non-heme Fe(II) to catalyze the addition of hydroxyl groups to the aromatic ring, an initial step in the oxidative degradation of aromatic compounds. RHOs are composed of either two or three protein components, and are comprised of an electron transport chain (ETC) and an oxygenase. The ETC transfers reducing equivalents from the electron donor to the oxygenase component, which in turn transfers electrons to the oxygen molecules. The oxygenase components are oligomers, either (alpha)n or (alpha)n(beta)n. The alpha subunits are the catalytic components and have an N-terminal domain, which binds a Rieske-like 2Fe-2S cluster, and the C-terminal catalytic domain which binds the non-heme Fe(II). The Fe(II) is co-ordinated by conserved His and Asp residues. Oxygenases belonging to this subgroup include the alpha subunits of carbazole 1,9a-dioxygenase, phthalate dioxygenase, vanillate O-demethylase, Pseudomonas putida 2-oxoquinoline 8-monooxygenase, and Comamonas testosteroni T-2 p-toluenesulfonate dioxygenase. It also includes the C-terminal domain of the lignin biphenyl-specific O-demethylase (LigX) of the 5,5'-dehydrodivanillic acid O- demethylation system of Sphingomonas paucimobilis SYK-6. This subfamily belongs to the SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646  152 YTEWRGDYRYVLDNVMDPMHGTYLHKQS--HSMSEGESQARFVTRDTDTGFIF---EKDGQRGVNFDWTE---WADTGMH 223
Cdd:cd08878   5 YRHIDCNWLQVVENLMDPSHVSFVHRSSigRDAADLPSGPPKEVEEVPRGVTYrrwREDEDPPPFGFEGPvdrWRVIEFL 84

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646  224 W---MRLEIPYPKTGGPGGNFHIVGS--YTPIARDLCAVF--HWR-CRPLTGWQRDTWrfLYRNRLEARHwAVLEQDREM 295
Cdd:cd08878  85 LpnvLLIDPGVAPAGTREQGVRMRVThwITPIDETTTHYFwfFVRnFAPDEEKKDDEE--LTETLRSGLS-GAFNEDKEA 161

                       170       180       190
                ....*....|....*....|....*....|.
gi 9949646  296 LEFMEP---DANQRENLYQHDLGLVRLRRHL 323
Cdd:cd08878 162 VEAQQRiidRDPTREHLGLSDKGIVRFRRLL 192

Rieske domain; a [2Fe-2S] cluster binding domain commonly found in Rieske non-heme iron oxygenase (RO) systems such as naphthalene and biphenyl dioxygenases, as well as in plant/cyanobacterial chloroplast b6f and mitochondrial cytochrome bc(1) complexes. The Rieske domain can be divided into two subdomains, with an incomplete six-stranded, antiparallel beta-barrel at one end, and an iron-sulfur cluster binding subdomain at the other. The Rieske iron-sulfur center contains a [2Fe-2S] cluster, which is involved in electron transfer, and is liganded to two histidine and two cysteine residues present in conserved sequences called Rieske motifs. In RO systems, the N-terminal Rieske domain of the alpha subunit acts as an electron shuttle that accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron in the alpha subunit C-terminal domain to be used for catalysis.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 9949646   19 WYPICPVGFI-EDKPVSLRRLGYKLAVWRDTDGTLHALEDHCPHRGAPLSRGVNLGDRLQCPYHG 82
Cdd:cd03467   1 WVVVGALSELpPGGGRVVVVGGGPVVVVRREGGEVYALSNRCTHQGCPLSEGEGEDGCIVCPCHG 65

Small subunit of nitrite reductase (NirD) family, Rieske domain; composed of proteins similar to the Bacillus subtilis small subunit of assimilatory nitrite reductase containing a Rieske domain. The Rieske domain is a [2Fe-2S] cluster binding domain involved in electron transfer. Assimilatory nitrate and nitrite reductases convert nitrate through nitrite to ammonium.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 9949646   19 WYPICPVgfiEDKPVSLRRL----GYKLAVWRDTDGTLHALEDHCPHRGAPLSRGVNLGDRLQCPYHG 82
Cdd:cd03530   1 WIDIGAL---EDIPPRGARKvqtgGGEIAVFRTADDEVFALENRCPHKGGPLSEGIVHGEYVTCPLHN 65

AIFL (apoptosis-inducing factor like) family, N-terminal Rieske domain; members of this family show similarity to human AIFL, containing an N-terminal Rieske domain and a C-terminal pyridine nucleotide-disulfide oxidoreductase domain (Pyr_redox). The Rieske domain is a [2Fe-2S] cluster binding domain involved in electron transfer. AIFL shares 35% homology with human AIF (apoptosis-inducing factor), mainly in the Pyr_redox domain. AIFL is predominantly localized to the mitochondria. AIFL induces apoptosis in a caspase-dependent manner.

                        10        20        30
                ....*....|....*....|....*....|...
gi 9949646   50 GTLHALEDHCPHRGAPLSRGVNLGDRLQCPYHG 82
Cdd:cd03478  31 GEVHAIGAKCPHYGAPLAKGVLTDGRIRCPWHG 63

Rieske non-heme iron oxygenase (RO) family, Rieske ferredoxin component; composed of the Rieske ferredoxin component of some three-component RO systems including biphenyl dioxygenase (BPDO) and carbazole 1,9a-dioxygenase (CARDO). The RO family comprise a large class of aromatic ring-hydroxylating dioxygenases found predominantly in microorganisms. These enzymes enable microorganisms to tolerate and even exclusively utilize aromatic compounds for growth. ROs consist of two or three components: reductase, oxygenase, and ferredoxin (in some cases) components. The ferredoxin component contains either a plant-type or Rieske-type [2Fe-2S] cluster. The Rieske ferredoxin component in this family carries an electron from the RO reductase component to the terminal RO oxygenase component. BPDO degrades biphenyls and polychlorinated biphenyls. BPDO ferredoxin (BphF) has structural features consistent with a minimal and perhaps archetypical Rieske protein in that the insertions that give other Rieske proteins unique structural features are missing. CARDO catalyzes dihydroxylation at the C1 and C9a positions of carbazole. Rieske ferredoxins are found as subunits of membrane oxidase complexes, cis-dihydrodiol-forming aromatic dioxygenases, bacterial assimilatory nitrite reductases, and arsenite oxidase. Rieske ferredoxins are also found as soluble electron carriers in bacterial dioxygenase and monooxygenase complexes.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 9949646   19 WYPICPVGFI-EDKPVSLRRLGYKLAVWRdTDGTLHALEDHCPHRGAPLSRGVNLGDRLQCPYHG 82
Cdd:cd03528   1 WVRVCAVDELpEGEPKRVDVGGRPIAVYR-VDGEFYATDDLCTHGDASLSEGYVEGGVIECPLHG 64

Rieske non-heme iron oxygenase (RO) family, Anthranilate 1,2-dioxygenase (AntDO) subfamily, N-terminal Rieske domain of the oxygenase alpha subunit; ROs comprise a large class of aromatic ring-hydroxylating dioxygenases that enable microorganisms to tolerate and utilize aromatic compounds for growth. The oxygenase alpha subunit contains an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis. AntDO converts anthranilate to catechol, a naturally occurring compound formed through tryptophan degradation and an important intermediate in the metabolism of many N-heterocyclic compounds such as indole, o-nitrobenzoate, carbazole, and quinaldine.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 9949646   46 RDTDGTLHALEDHCPHRGAPLS--RGVNLGDRLQCPYHGVEVRCDGVTARVP 95
Cdd:cd03538  52 RHTDGSVHVLYNRCPHKGTKIVsdGCGNTGKFFRCPYHAWSFKTDGSLLAIP 103

Rieske non-heme iron oxygenase (RO) family, Nathphalene 1,2-dioxygenase (NDO) subfamily, N-terminal Rieske domain of the oxygenase alpha subunit; ROs comprise a large class of aromatic ring-hydroxylating dioxygenases that enable microorganisms to tolerate and utilize aromatic compounds for growth. The oxygenase alpha subunit contains an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis. NDO is a three-component RO system consisting of a reductase, a ferredoxin, and a hetero-hexameric alpha-beta subunit oxygenase component. NDO catalyzes the oxidation of naphthalene to cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene (naphthalene cis-dihydrodiol) with the consumption of O2 and NAD(P)H. NDO has a relaxed substrate specificity and can oxidize almost 100 substrates. Included in its varied activities are the enantiospecific cis-dihydroxylation of polycyclic aromatic hydrocarbons and benzocycloalkenes, benzylic hydroxylation, N- and O-dealkylation, sulfoxidation and desaturation reactions.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....
gi 9949646   44 VWRDTDGTLHALEDHCPHRGAPLSRgVNLGD--RLQCPYHGVEVRCDGVTARVP 95
Cdd:cd03535  30 VCRDEDGEIRAMFNSCRHRGMQVCR-AEMGNtsHFRCPYHGWTYRNTGRLVGVP 82

Rieske non-heme iron oxygenase (RO) family, Ortho-halobenzoate-1,2-dioxygenase (OHBDO)-like subfamily, N-terminal Rieske domain of the oxygenase alpha subunit; composed of the oxygenase alpha subunits of OHBDO, salicylate 5-hydroxylase (S5H), terephthalate 1,2-dioxygenase system (TERDOS) and similar proteins. ROs comprise a large class of aromatic ring-hydroxylating dioxygenases that enable microorganisms to tolerate and utilize aromatic compounds for growth. The oxygenase alpha subunit contains an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis. OHBDO converts 2-chlorobenzoate (2-CBA) to catechol as well as 2,4-dCBA and 2,5-dCBA to 4-chlorocatechol, as part of the chlorobenzoate degradation pathway. Although ortho-substituted chlorobenzoates appear to be particularly recalcitrant to biodegradation, several strains utilize 2-CBA and the dCBA derivatives as a sole carbon and energy source. S5H converts salicylate (2-hydroxybenzoate), a metabolic intermediate of phenanthrene, to gentisate (2,5-dihydroxybenzoate) as part of an alternate pathway for naphthalene catabolism. S5H is a multicomponent enzyme made up of NagGH (the oxygenase components), NagAa (the ferredoxin reductase component), and NagAb (the ferredoxin component). The oxygenase component is made up of alpha (NagG) and beta (NagH) subunits. TERDOS is present in gram-positive bacteria and proteobacteria where it converts terephthalate (1,4-dicarboxybenzene) to protocatechuate as part of the terephthalate degradation pathway. The oxygenase component of TERDOS, called TerZ, is a hetero-hexamer with 3 alpha (TerZalpha) and 3 beta (TerZbeta) subunits.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 9949646   27 FIEDKPVslrrlgyklAVWRDTDGTLHALEDHCPHRGAPLSRGVNlGDR--LQCPYHGVEVRCDGVTARVPGSPGCKLEG 104
Cdd:cd03545  45 FVGDTPV---------VVTRAEDGSLHAWVNRCAHRGALVCRERR-GNDgsLTCVYHQWAYDLKGNLKGVPFRRGLKGQG 114

                ....*.
gi 9949646  105 SQATRF 110
Cdd:cd03545 115 GMPKDF 120

YhfW family, C-terminal Rieske domain; YhfW is a protein of unknown function with an N-terminal DadA-like (glycine/D-amino acid dehydrogenase) domain and a C-terminal Rieske domain. The Rieske domain is a [2Fe-2S] cluster binding domain involved in electron transfer. It is commonly found in Rieske non-heme iron oxygenase (RO) systems such as naphthalene and biphenyl dioxygenases, as well as in plant/cyanobacterial chloroplast b6f and mitochondrial cytochrome bc(1) complexes. YhfW is found in bacteria, some eukaryotes and archaea.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 9949646   39 GYKLAVWRDTDGTLHALEDHCPHRGAPLSrgVNLGDR-LQCPYHGVEVRCDG 89
Cdd:cd03477  20 GKRLAVYRDEDGVLHTVSATCTHLGCIVH--WNDAEKsWDCPCHGSRFSYDG 69