This COG belongs to the functional category C, “”Energy production and conversion”". No functional information for this COG is given. The repeats in the protein sequence of OE2401F led to a high number of non-significant matches https://www.selleckchem.com/products/AZD6244.html in database searches. Thus it was not possible to identify a reliable set of orthologs from other organisms, and no conclusions about co-occurrence of this protein family with che or fla genes could be drawn. Close homologs were identified in the che and fla gene regions of the halophilic archaea N. pharaonis and H. marismortui. These homologs are, like in H. salinarum, adjacent to a DUF439 gene. Additionally, proteins with HEAT-like repeats

are present in all sequenced haloarchaeal genomes (the above mentioned, H. walsbyi, and H. salinarum) in other click here genomic context. For none of these proteins could any functional knowledge be obtained. Homologs of OE2402F and OE2404R are found generally and exclusively in archaeal che gene regions OE2402F and OE2404R are annotated as conserved hypothetical proteins. They are homologous to each other and belong to the protein family DUF439 [58] and to the cluster of orthologous groups COG2469. DUF439 is described as “”archaeal protein of unknown

function”", and COG2469 as “”uncharacterized conserved protein”". Homology searches showed that no members of the family DUF439 can be found outside the domain Archaea. Among the archaea, the presence of such a gene strictly correlated with the presence of che genes (see Additional file 6). The only exceptions were Methanocaldococcus jannaschii, which does not possess che genes but has a DUF439 homolog, and Methanosarcina barkeri, that has che genes but no DUF439. Examination of the genomic context revealed that the DUF439 genes are always located in the chemotaxis gene regions (Figure 5). The exceptions were two of the four paralogs in H. marismortui. In 10 out of 17 species the DUF439 gene is adjacent to CheY. Figure 5 Organization of chemotaxis genes in archaeal genomes. Known chemotaxis genes (indicated by gene letter) and genes coding for receptors

(Methyl-accepting chemotaxis proteins, MCP) are shown in blue. Genes coding ID-8 for proteins of the family DUF439 are shown in light blue and genes coding for HEAT domain proteins in cyan. Gray indicates that, where no name is given, the function of the coded protein is unknown, or the protein is probably unrelated to chemotaxis (S6: 30S ribosomal protein S6e). A//sign indicates separated SGC-CBP30 molecular weight genome regions. The asterisk indicates that this protein is interrupted by a frame-shift mutation. The only archaeal che gene regions without a DUF439 homolog are the che2 regions of the Methanosarcina species. In Methanosarcina barkeri this is the only che region, as this species does not contain the part of the genome where the che1 region in M. mazei and M. acetivorans is located [59–61]. The che gene region of M.