>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=96.97  E-value=0.004  Score=41.68  Aligned_cols=61  Identities=21%  Similarity=0.271  Sum_probs=42.4

Q ss_pred             CCCCCEEEEECCHHHHHHHHHHHHHHHCCCCEEEEECCCCCHHCCCCHHHHHHHCCCCCEEEEE
Q ss_conf             6997299995268899999999999973994399857465810008688999643679779997
Q gi|254780655|r  556 TPNAQVTIFSSGSELKIAVEACEILSSRNISTRVVSVPCFELFFEQSDSYRAQIIGSSPIKIAI  619 (673)
Q Consensus       556 ~~~~dv~iia~G~~v~~al~aa~~L~~~Gi~~~Vi~~~s~k~ld~~~~~~~~~il~~~~~~vti  619 (673)
T Consensus       262 apdAE~vIi~MGSvaeTieEtvdyL~~kG~KvGllkVrLYRPF~~---~~F~~~lP~svK~IAV  322 (1194)
T TIGR02176       262 APDAERVIIAMGSVAETIEETVDYLRSKGEKVGLLKVRLYRPFSA---ETFLAALPKSVKRIAV  322 (1194)
T ss_pred             CCCCCCEEEECCCHHHHHHHHHHHHHHCCCEEEEEEEEECCCCCH---HHHHHHCCCCCCEEEE
T ss_conf             702031044058566789999999972893276888751279858---9999842411012221