>TIGR02176 pyruv_ox_red pyruvate:ferredoxin (flavodoxin) oxidoreductase; InterPro: IPR011895 The oxidative decarboxylation of pyruvate to acetyl-CoA, a central step in energy metabolism, can occur by two different mechanisms . In mitochondria and aerobic bacteria this reaction is catalysed by the multienzyme complex pyruvate dehydrogenase using NAD as electron acceptor. In anaerobic organisms, however, this reaction is reversibly catalysed by a single enzyme using either ferrodoxin or flavodoxin as the electron acceptor. Pyruvate:ferrodoxin/flavodoxin reductases (PFORs) in this entry occur in both obligately and facultatively anaerobic bacteria and also some eukaryotic microorganisms. These proteins are single-chain enzymes containing a thiamin pyrophosphate cofactor for the cleavage of carbon-carbon bonds next to a carbonyl group, and iron-sulphur clusters for electron transfer. The Desulfovibrio africanus enzyme is currently the only PFOR whose three dimensional structure is known , . It is a homodimer where each subunit contains one thiamin pyrophosphate cofactor and two ferrodoxin-like 4Fe-S clusters and an atypical 4Fe-S cluster. Each monomer is composed of seven domains - domains I, II and VI make intersubunit contacts, while domains III, IV and V are located at the suface of the dimer, and domain VII forms a long arm extending over the other subunit. The cofactor is bound at the interface of domains I and VI and is proximal to the atypical 4Fe-S bound by domain VI, while the ferrodoxin-like 4Fe-S clusters are bound by domain V. Comparison of this enzyme with the multi-chain PFORs shows a correspondance between the domains in this enzyme and the subunits of the multi-chain enzymes.; GO: 0005506 iron ion binding, 0016903 oxidoreductase activity acting on the aldehyde or oxo group of donors, 0006118 electron transport.

Probab=97.79  E-value=1.4e-05  Score=59.29  Aligned_cols=104  Identities=25%  Similarity=0.404  Sum_probs=66.5

Q ss_pred             CHHHHHHHHHHHHHHHHCCCCCCCCCCCCCCCHHHHHHHHH-CCCCCCCC-----CCCCCCCC--CCCCCHHCCCHHHCC
Q ss_conf             98999999999999982789988778887888379989983-89867477-----75677878--885602100643290
Q gi|254780859|r   88 SSMVKKARAGVMEFLLINHPLDCPICDQGGECDLQDQAIFF-GFGSSRYS-----EEKRAVED--KSIGPLVKTVMNRCI  159 (700)
Q Consensus        88 s~~v~~~r~~vle~ll~nHpldCp~Cd~~GeC~LQd~~~~~-g~~~~r~~-----~~k~~~~~--~~~~p~i~~d~~rCI  159 (700)
T Consensus       640 ~~~~~eFV~nv~~----------pi~~q~GD-~lpVS~~~~~GmeDG~fPlGTt~~EKRgvA~~vP~W~------~d~Ci  702 (1194)
T TIGR02176       640 AEDAPEFVKNVVR----------PIAAQEGD-DLPVSAFPARGMEDGTFPLGTTAFEKRGVALEVPVWK------SDNCI  702 (1194)
T ss_pred             CCCCCHHHHHHHH----------HHHHCCCC-CCCHHHHHCCCCCCCCCCCHHHHHHHHHHCCCCCCCC------CCCCC
T ss_conf             7747478999888----------88625889-8765777438886888862020034531203187056------56653


Q ss_pred             CCCHHHHHHH------------HCC----CCCCEEEECCCCC---CEEEECCCCCCCCCCCCCEEECCCCC
Q ss_conf             1002364543------------206----8740033306664---12662058755565466222012121
Q gi|254780859|r  160 HCTRCVRFIT------------EVA----GVSELGLVGRGEN---AEITTYLEQSLTSEMQGNIIDLCPVG  211 (700)
Q Consensus       160 ~C~RCVR~c~------------Ev~----g~~~lg~~~RG~~---~~i~~~~~~~~~~e~~Gncvd~CPvG  211 (700)
T Consensus       703 qCnqCa~VCPHaaIR~~l~~~ee~~~AP~~F~~~d~kGK~~~g~kyrIQv---s~~DCtGCglCvd~CPa~  770 (1194)
T TIGR02176       703 QCNQCAFVCPHAAIRPFLLDEEELEKAPEGFKSLDAKGKELEGLKYRIQV---SVEDCTGCGLCVDICPAK  770 (1194)
T ss_pred             CCCCCCCCCCHHHHHHHHCCCHHHHCCCCCCEEECCCCCCCCCCCEEEEE---CCCCCCCCCCCCCCCCCC
T ss_conf             47885433764787776427157635898647713436788987006874---275035763420358588