>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=95.04  E-value=0.0051  Score=38.30  Aligned_cols=98  Identities=18%  Similarity=0.304  Sum_probs=49.2

Q ss_pred             HHHHHHHHHHHHHHHHHHHHHHHHC------CCCCCCCCCCCCCCCCCHHCC-----CEEEEEECCCCCCCEECCCCHHH
Q ss_conf             8999999999999999999999840------698522578757756800057-----23787405887422134522325
Q gi|254780861|r    4 FRCNVSFLFLKEFVGAFFLCLRYFF------KAKTTINYPFEKGSTSPRFRG-----EHALRRYPNGEERCIACKLCEAI   72 (163)
Q Consensus         4 ~~~~~~~~~~~~~~~gl~~t~k~~~------~~~~T~~YP~e~~~~~~rfRG-----~~~l~~~~~~~ekCi~C~~C~~~   72 (163)
T Consensus       589 lK~~I~ksYGK---KG~~vV~~N~~AvD~~v~~l~~v~vp~~w~~~~~~~~~ri~~~~~eFV--------------~nv~  651 (1194)
T TIGR02176       589 LKKSIEKSYGK---KGEEVVQKNIKAVDKAVESLHEVKVPAEWKDAEEEPKARIAEDAPEFV--------------KNVV  651 (1194)
T ss_pred             HHHHHHHHCCC---CCHHHHHHHHHHHHHHHHCCEECCCCHHHHCCHHCCCCCCCCCCCHHH--------------HHHH
T ss_conf             88998850489---777889877999977733245324763661411237755477474789--------------9988


Q ss_pred             HHH-----CCCCCCCCCC--CCCCCE---------E-----EEEEEEEHHHCCCCCCCHHHCCCCEEEC
Q ss_conf             330-----8832101224--544733---------5-----7788850555586887233378310303
Q gi|254780861|r   73 CPA-----QAITIESGPR--CHDGTR---------R-----TVRYDIDMIKCIYCGLCQEACPVDAIVE  120 (163)
Q Consensus        73 CP~-----~aI~i~~~~~--~~~~~~---------~-----~~~~~id~~~Ci~Cg~Cv~vCP~~AI~~  120 (163)
T Consensus       652 ~pi~~q~GD~lpVS~~~~~GmeDG~fPlGTt~~EKRgvA~~vP~W~~d--~CiqCnqCa~VCPHaaIR~  718 (1194)
T TIGR02176       652 RPIAAQEGDDLPVSAFPARGMEDGTFPLGTTAFEKRGVALEVPVWKSD--NCIQCNQCAFVCPHAAIRP  718 (1194)
T ss_pred             HHHHHCCCCCCCHHHHHCCCCCCCCCCCHHHHHHHHHHCCCCCCCCCC--CCCCCCCCCCCCCHHHHHH
T ss_conf             888625889876577743888688886202003453120318705656--6534788543376478777