Disease relevance of DPS1

• The wild-type transcript of Escherichia coli tRNASec, characterized by a peculiar core architecture and a large variable region, was shown to be aspartylatable by yeast AspRS [1].
• With AspRS from Thermus thermophilus, the better crystalline quality of the space-grown crystals within APCF is correlated with higher quality of the derived electron density maps [2].
• Asparaginyl-tRNA formation in Pseudomonas aeruginosa PAO1 involves a nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) which forms Asp-tRNA(Asp) and Asp-tRNA(Asn), and a tRNA-dependent amidotransferase which transamidates the latter into Asn-tRNA(Asn) [3].

High impact information on DPS1

• Two of them, GlnRS and AspRS, have been cocrystallized with their cognate tRNA [4].
• DPS1 and DPS2 are located approximately 30 kb from the left arm of chromosome III, well removed from HML, HMR, and MAT [5].
• ATP sulfurylases (ATPSs) are ubiquitous enzymes that catalyse the primary step of intracellular sulfate activation: the reaction of inorganic sulfate with ATP to form adenosine-5'-phosphosulfate (APS) and pyrophosphate (PPi) [6].
• We have analysed the crystal structure of the native enzyme at 1.95 Angstroms resolution using multiple isomorphous replacement (MIR) and, subsequently, the ternary enzyme product complex with APS and PPi bound to the active site [6].
• Adenosine 5'-phosphosulfate (APS) was shown to be a much more efficient substrate than PAPS when the activity of the PRH proteins was tested by their ability to convert 35S-labeled substrate to acid-volatile 35S-sulfite [7].

Chemical compound and disease context of DPS1

• This C-terminal region contains SH-1 (Cys-508) and has homology to MET14 (S. cerevisiae), CYSC (E. coli), and NODQ (Rhizobium meliloti), i.e. adenosine 5'-phosphosulfate (APS) kinase [8].

Biological context of DPS1

• Eight ORFs show no homology to known sequences in the database, three small ORFs are internal and complementary to larger ones and L1301 is complementary overlapping the ATS/DPS1 gene [9].
• These results, which can be explained by the crystal structure of the native enzyme complexed with its substrates, confirm the structural importance of Pro-273 for dimerization and clearly establish the functional interdependence of the AspRS subunits [10].
• Finally, acylation efficiencies of AspRS mutants in the presence of pure tRNA(Asp)and non-fractionated tRNAs indicate that residues involved in the binding of identity bases also discriminate against non-cognate tRNAs [11].
• Here, we attempt to locate these functional features by using a genetic selection method to screen a randomly mutated yeast AspRS library for mutations lethal for cell growth [12].
• To our knowledge, this is the first report of the cloning and characterization of plant genes that encode proteins with APS reductase activity and supports the suggestion that APS can be utilized directly, without activation to PAPS, as an intermediary substrate in reductive sulfate assimilation [7].

Anatomical context of DPS1

• In 3T3-L1 adipocytes, insulin receptor activation was accompanied by the APS-dependent recruitment of Asb6 [13].
• In NIH-3T3 cells that express the insulin receptor, Enigma and APS were partially co-localised with F-actin in small ruffling structures [14].
• SH2-Balpha contains pleckstrin-homology ('PH') and Src homology 2 (SH2) domains and is closely related to APS (adapter protein with a PH domain and an SH2 domain) and lnk, adapter proteins first identified in lymphocytes [15].

Associations of DPS1 with chemical compounds

• Altogether, it appears that recognition of a tRNA by AspRS is more governed by the presence of the aspartate identity set than by the structural framework that carries this set [1].
• The interaction of wild-type and mutant yeast tRNA(Asp) transcripts with yeast aspartyl-tRNA synthetase (AspRS; EC 6.1.1.12) has been probed by using iodine cleavage of phosphorothioate-substituted transcripts [16].
• In contrast, adenosine-5'-phosphosulfate (APS = product Q), the immediate product of the SO4(2-)-dependent reaction, is a linear inhibitor of the P. chrysogenum enzyme, competitive with both MgATP and MoO4(2-) (Kiq = 36-73 nM) [17].
• However, in the presence of orthophosphate, the APS is irreversibly converted to ADP [18].
• The APS adapter protein plays a pivotal role in coupling the insulin receptor to CAP and c-Cbl in the phosphatidylinositol 3-kinase-independent pathway of insulin-stimulated glucose transport [13].

Analytical, diagnostic and therapeutic context of DPS1

• Here we show that two alpha2p/Mcm1p-binding sites, DPS1 and DPS2, control donor selection [5].
• Precise deletion of only DPS1 and DPS2 results in random selection of donor loci and in a cells without affecting selection in alpha cells [5].
• Heterodimers of AspRS were produced in vivo by overexpression of their respective subunit variants from plasmid-encoded genes and purified to homogeneity in one HPLC step [10].
• In connection with this, we explored by site-directed mutagenesis the functional role of the interactions which, as revealed by the crystallographic structure, occur between the wobble base of yeast tRNA(Asp) and two residues of yeast AspRS [19].
• [3'-32P]PAPS was synthesized from adenosine 5'-phosphosulfate (APS) and [gamma-32P]ATP using APS kinase prepared from yeast and was purified by reverse-phase ion pair high performance liquid chromatography [20].

References