A nhaD Na+/H+ antiporter and a pcd homologues are among the Rhodothermus marinus complex I genes.
The NADH:menaquinone oxidoreductase (Nqo) is one of the enzymes present in the respiratory chain of the thermohalophilic bacterium Rhodothermus marinus. The genes coding for the R. marinus Nqo subunits were isolated and sequenced, clustering in two operons [nqo1 to nqo7 (nqoA) and nqo10 to nqo14 (nqoB)] and two independent genes (nqo8 and nqo9). Unexpectedly, two genes encoding homologues of a NhaD Na+/H+ antiporter (NhaD) and of a pterin-4alpha-carbinolamine dehydratase (PCD) were identified within nqoB, flanked by nqo13 and nqo14. Eight conserved motives to harbour iron-sulphur centres are identified in the deduced primary structures, as well as two consensus sequences to bind nucleotides, in this case NADH and FMN. Moreover, the open-reading-frames of the putative NhaD and PCD were shown to be co-transcribed with the other complex I genes encoded by nqoB. The possible role of these two genes in R. marinus complex I is discussed.
Melo
Ana M P
AM
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, Apartado 127, 2781-901 Oeiras, Portugal.
Lobo
Susana A L
SA
Sousa
Filipa L
FL
Fernandes
Andreia S
AS
Pereira
Manuela M
MM
Hreggvidsson
Gudmundur O
GO
Kristjansson
Jacob K
JK
Saraiva
Lígia M
LM
Teixeira
Miguel
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D017931:DNA Primers; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045245:Rhodothermus / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics*
D001426:Bacterial Proteins; D017931:DNA Primers; D017923:Sodium-Hydrogen Exchangers