Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D02011 (FAD)
 5,530 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The single-domain coenzyme A (CoA)-binding protein is conserved in bacteria, archaea, and a few eukaryal taxa. It consists of a Rossmann-fold domain, belonging to the FAD/NAD(P)-binding ;superfamily. The crystal structure of the Thermus thermophilus single-domain CoA-binding protein, TTHA1899, has been determined and it has been demonstrated, by isothermal titration calorimetry, that the protein interacts with CoA [Wada T. et al. Acta Crystallogr D Biol Crystallogr 59 (2003) 1213]. In the present study, we determined the crystal structures of an orthologous protein from the archaeon Pyrococcus horikoshii (PH1109), alone and complexed with CoA, at 1.65 A and 1.70 A resolutions, respectively, and that of P. furiosus protein (PF0725) in the CoA-bound form at 1.70 A. The CoA-bound structures are very similar to each other, revealing that the Pyrococcus proteins bind CoA in a 1:1 stoichiometry. Five loop-containing regions form the CoA-binding groove, to which the CoA molecule is docked. A comparison of the structures and the sequences of the Pyrococcus proteins with those of the T. theromphilus orthologue TTHA1899 indicated that archaeal and bacterial single-domain CoA-binding proteins share the same CoA-binding mode. Nevertheless, many of the peripheral residues involved in the hydrogen-bonding/electrostatic interactions with CoA are not strictly conserved in the family. The CoA interaction of the single-domain CoA-binding proteins is significantly different and much more extensive than that of the multi-subunit/multi-domain CoA-binding protein succinyl-CoA synthetase.
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PMID:Structural basis of CoA recognition by the Pyrococcus single-domain CoA-binding proteins. 1734 53

A mitochondrion-like organelle (MLO) was isolated from isotonic homogenates of Blastocystis. The organelle sedimented at 5000 g for 10 min, and had an isopycnic density in sucrose of 1.2 g ml(-1). Biochemical characterization enabled the demonstration of several key enzymes that allowed the construction of a metabolic pathway consisting of an incomplete Krebs cycle linked to the oxygen-sensitive enzymes pyruvate : NADP(+) oxidoreductase (PNO), acetate : succinate CoA transferase (ASCT) and succinate thiokinase (STK), which cumulatively are responsible for recycling CoA and generating ATP. The organelle differs from typical aerobic mitochondria in possessing an oxygen-sensitive PNO that can use FAD(+) or FMN(+) as electron acceptor but is inactive with NAD(+), Spinacia oleracea ferredoxin or Clostridium pasteurianum ferredoxin. A gene with 77 % sequence similarity to the PNO mitochondrion precursor cluster from Euglena gracilis sp[Q941N5] was identified in the Blastocystis genome database. A second cluster with 56 % sequence similarity to the pyruvate : ferredoxin oxidoreductase (PFOR) from Trichomonas vaginalis was also identified, which is in agreement with the concept that the PNO gene arose through the fusion of a eubacterial gene for PFOR with the gene for NADPH : cytochrome p450 reductase. Hydrogenase activity was not detected under the conditions used in this study. The Blastocystis oranelle therefore demonstrates significant biochemical differences from traditional mitochondria and hydrogenosomes, but possesses features of both. Based upon the results of this study, the Blastocystis organelle falls into the category of a MLO.
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PMID:Biochemical characterization of a mitochondrial-like organelle from Blastocystis sp. subtype 7. 1875 9