Conserved Protein Domain Family
QFR_TypeD_subunitC

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cd00546: QFR_TypeD_subunitC 
Click on image for an interactive view with Cn3D
Quinol:fumarate reductase (QFR) Type D subfamily, 15kD hydrophobic subunit C; QFR couples the reduction of fumarate to succinate to the oxidation of quinol to quinone, the opposite reaction to that catalyzed by the related protein, succinate:quinine oxidoreductase (SQR). QFRs oxidize low potential quinols such as menaquinol and are involved in anaerobic respiration with fumarate as the terminal electron acceptor. SQR and QFR share a common subunit arrangement, composed of a flavoprotein catalytic subunit, an iron-sulfur protein and one or two hydrophobic transmembrane subunits. Members of this subfamily are classified as Type D as they contain two transmembrane subunits (C and D) and no heme groups. The structural arrangement allows efficient electron transfer between the catalytic subunit, through iron-sulfur centers, and the transmembrane subunit containing the electron donor (quinol). The quinone binding site resides in the transmembrane subunits.
Statistics
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PSSM-Id: 238306
View PSSM: cd00546
Aligned: 15 rows
Threshold Bit Score: 127.057
Threshold Setting Gi: 34104674
Created: 7-Mar-2002
Updated: 17-Jan-2013
Structure
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Program:
Drawing:
Aligned Rows:
 
Conserved site includes 4 residues -Click on image for an interactive view with Cn3D
Feature 1:proximal quinone binding site [chemical binding site]
Evidence:
  • Structure:1L0V; Escherichia coli Quinol-Fumarate Reductase binds the proximal menaquinone; contacts at 3.5A
    View structure with Cn3D
  • Comment:Escherichia coli QFR binds two menaquinone molecules, one proximal and the other distal to the [3Fe-4S] cluster of the iron-sulfur protein.
  • Comment:Known inhibitors, such as HQNO, block the binding of menaquinone at the proximal binding site. A reduced quinol bound at this site is thought to be the immediate electron donor to the redox cofactors in the soluble subunits.

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                               ##                                                      
1L0V_C        4 RKPYVRPMTSTWWKKLpFYRFYMLREGTAVPAVWFSIELIFGLFALKNgp---eAWAGFVDFLQNPVIVIINLITLAAAL 80
gi 1169739    4 RKKYVRPMTATWWQKLdFYKAYMLREATSVFAVWFCIVLLYGVLCFASnpmpglGILSFIEFLRNPIVVFLNIITLIATL 83
gi 37527971   5 RKPYIRSMAPNWWQKLgFYRFYILRESTAVTTMWFSILLIYGLFALKGgt---qSWHEFVTFLQNPVILLVNIITLLGAL 81
gi 32029496   8 RRRYVREVKATWWKKLdFYKLYIMREATAIPSLWFSLVLLYGVICLGQkd---gLQSDFIPFLQNPIVIILNIIALAAAI 84
gi 15602064   8 RKKYVREMKPTWWKKLdFYKLYIAREATAIPTLWFCLVLLYGVISLGSl----dSFGNFISFLKNPIVIILNIITLGAML 83
gi 46143534   7 RKAYVREMKANWWTKSsFYKMYMVREATCLATVWFCLVLLHGVISLGGg-----SLDGFISFLQNPIVFILNVISIAALL 81
gi 52425709   7 RNKYVREVTPTWWKSWsFYKFYMLRESSAIPTVWFCLVLLYGVFCLTTan---gFVEKFIPFLQNPVVVILNLISLALLL 83
gi 34104674   4 RKPYVRPMEGWWKKNP-YFIEYMIHEGTALFVAAYGFVLLFGLWRLSQge---aAWNGFVAALRSPLSMLLHLILLAMIG 79
gi 75431436   8 RNKYVREITPTWWKSWdFYRFYMVREATAVPTVWFCLVLLYGVFSLADn----tFATDFVGFMQNPIVMILNIISLAAML 83
gi 46914888   4 RKPYVREMTRTWWKDDpFYRFYMVREATILPLIFFTICLTFGLGCLVKgp---eAWAGWLSFMSNPIVVVLNILALLGSL 80
                        90       100       110       120
                ....*....|....*....|....*....|....*....|....*...
Feature 1            #  #                                       
1L0V_C       81 LHTKTWFELAPKA-ANIIVKdekmgpePIIKSLWAVTVVATIVILFVA 127
gi 1169739   84 YHTVTYFLMTPKV-MNIIVKnerlphtVVRNALWAVTALVSVIALVLV 130
gi 37527971  82 LHTKTWFELAPKA-ANIVIKgekmgsgPVIKLLWAVTIIVTMIILGIA 128
gi 32029496  85 LNTVTYFFMTPKV-LNIVYKneklnpnVITIGMWAVTAVVSILALVLI 131
gi 15602064  84 LNTVTYYVMTPKV-LNIIVKnerinpnIITMALWAVTAFISLVILVFM 130
gi 46143534  82 YHAATLYVMTPQV-LTFIVKnervnpnILKNALWAVTGLVSLVALVCT 128
gi 52425709  84 LHAFTLFQMTGEV-MSGSLGlk---seVIQKALKVLFAIVTVVALVLV 127
gi 34104674  80 YHGYTWFKIMPRTlPPLIIGgrrvsatAITAGGFAATLLASLALLGVV 127
gi 75431436  84 LHAFTLFTMTGEV-MSNSTGlk---aeVIKKALQIAFAVVSVIGLILA 127
gi 46914888  81 FHAQTFFSMMPQV-MPITIKgkkldktIIVLAQWAAVAAISLFVLVLV 127

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