Oxygen sensor diguanylate cyclase/c-di-GMP phosphodiesterase

Oxygen sensor diguanylate cyclase/c-di-GMP phosphodiesterase(InterPro Protein Domain record)

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Oxygen sensor diguanylate cyclase/c-di-GMP phosphodiesterase

InterPro Protein Domain record

description http://metadb.riken.jp/db/SciNetS_rib124i/prib124u1i

Members of this group are signal transduction proteins that are direct oxygen sensors and are involved in regulation of cellular processes via the effector molecule cyclic diguanylate (c-di-GMP, bis(3',5')-cyclic diguanylic acid). They contain PAS/PAC, GGDEF, and EAL domains and have diguanylate cyclase and phosphodiesterase activities. Related groups with similar domain architectures contain different versions of PAS/PAC domain, and are thought to have different, often not yet determined biological functions (e.g., <db_xref db="PIRSF" dbkey="PIRSF036629"/>, <db_xref db="PIRSF" dbkey="PIRSF036377"/> amongst others). <taxon tax_id="562">Escherichia coli</taxon> Dos (YddU) and Acetobacter xylinum (Gluconacetobacter xylinus) PdeA1 proteins have been shown to be direct, haem-based oxygen sensors [<cite idref="PUB00015695"/>, <cite idref="PUB00015830"/>, <cite idref="PUB00015702"/>]. Their N-terminal PAS domains are responsible for haem-binding [<cite idref="PUB00015695"/>, <cite idref="PUB00015702"/>]. PAS/PAC is a ubiquitous intracellular sensory domain. It is located in the cytoplasm and sense changes in redox potential in the electron transport system or overall cellular redox status. PAS domains can monitor changes in light, oxygen or small ligands in a cell, and sense environmental factors that cross the cell membrane and/or affect cell metabolism [<cite idref="PUB00015791"/>, <cite idref="PUB00007364"/>, <cite idref="PUB00015676"/>]. In the haem-containing subgroup of PAS domains, the haem pocket acts as a ligand-specific trap [<cite idref="PUB00015810"/>]. The ligand binding to a haem-containing PAS domain leads to either activation or inhibition of a regulated (catalytic) domain (here, GGDEF and/or EAL domains). Phosphodiesterase activity with cAMP of E. coli Dos has been shown to be regulated by the haem redox state [<cite idref="PUB00015830"/>]. Similarly, Acetobacter xylinum PdeA1 is regulated by reversible binding of O2 to the haem [<cite idref="PUB00015702"/>]. The catalytic function of the members of this group has also been experimentally determined. Cyclic di-GMP (c-di-GMP) is the specific nucleotide regulator of beta-1,4-glucan (cellulose) synthase in Acetobacter xylinum [<cite idref="PUB00015649"/>]. In a study of the regulation of biosynthesis of extracellular cellulose in Acetobacter xylinum [<cite idref="PUB00015649"/>], the search for the enzymes that synthesise and hydrolyse cyclic di-GMP resulted in the identification of six proteins with identical domain architecture containing PAS, GGDEF and EAL domains. Three of them exhibited diguanylate cyclase activity (Dgc1-3), and three others - phosphodiesterase activity (PdeA1-3) [<cite idref="PUB00015649"/>, <cite idref="PUB00015702"/>]. Likewise, E. coli Dos has been shown to have phosphodiesterase activity [<cite idref="PUB00015830"/>]. Genetic complementation using genes from three different bacteria encoding proteins with GGDEF domains as the only element in common indicate that the GGDEF domain is responsible for the diguanylate cyclase activity of these proteins [<cite idref="PUB00015641"/>]. Even prior to these results, the notion that the GGDEF domain is a diguanylate cyclase was supported by the detailed analysis of its sequence, which shows conservation of the proposed nucleotide-binding loop in alignment with eukaryotic adenylate cyclases [<cite idref="PUB00007061"/>]. By exclusion, the EAL domain emerged as the best candidate for the role of c-di-GMP phosphodiesterase. Indeed, the sequence of this domain contains several conserved aspartates, which could participate in metal binding and form a phosphodiesterase active site [<cite idref="PUB00007150"/>]. It is not clear what differences make one subgroup of these proteins to act as phosphodiesterases, and another - as diguanylate cyclases, while containing both domains. PAS, GGDEF and EAL domains are found in many other signal transduction proteins with various domain architectures (e.g., <db_xref db="PIRSF" dbkey="PIRSF006638"/>, <db_xref db="PIRSF" dbkey="PIRSF036556"/>, <db_xref db="INTERPRO" dbkey="IPR014408"/>, <db_xref db="PIRSF" dbkey="PIRSF036390"/>, and many others). For additional information please see [<cite idref="PUB00015783"/>, <cite idref="PUB00015697"/>].

label http://www.w3.org/2000/01/rdf-schema#label