6t1b
Crystal structure of YlmD from Geobacillus stearothermophilus in complex with inosineCrystal structure of YlmD from Geobacillus stearothermophilus in complex with inosine
Structural highlights
FunctionPURNU_GEOS3 Purine nucleoside enzyme that catalyzes the phosphorolysis of adenosine and inosine nucleosides, yielding D-ribose 1-phosphate and the respective free bases, adenine and hypoxanthine (PubMed:31978345). Also catalyzes the phosphorolysis of S-methyl-5'-thioadenosine into adenine and S-methyl-5-thio-alpha-D-ribose 1-phosphate (PubMed:31978345). Also has adenosine deaminase activity (PubMed:31978345).[1] Publication Abstract from PubMedMutations in FAMIN cause arthritis and inflammatory bowel disease in early childhood, and a common genetic variant increases the risk for Crohn's disease and leprosy. We developed an unbiased liquid chromatography-mass spectrometry screen for enzymatic activity of this orphan protein. We report that FAMIN phosphorolytically cleaves adenosine into adenine and ribose-1-phosphate. Such activity was considered absent from eukaryotic metabolism. FAMIN and its prokaryotic orthologs additionally have adenosine deaminase, purine nucleoside phosphorylase, and S-methyl-5'-thioadenosine phosphorylase activity, hence, combine activities of the namesake enzymes of central purine metabolism. FAMIN enables in macrophages a purine nucleotide cycle (PNC) between adenosine and inosine monophosphate and adenylosuccinate, which consumes aspartate and releases fumarate in a manner involving fatty acid oxidation and ATP-citrate lyase activity. This macrophage PNC synchronizes mitochondrial activity with glycolysis by balancing electron transfer to mitochondria, thereby supporting glycolytic activity and promoting oxidative phosphorylation and mitochondrial H(+) and phosphate recycling. FAMIN Is a Multifunctional Purine Enzyme Enabling the Purine Nucleotide Cycle.,Cader MZ, de Almeida Rodrigues RP, West JA, Sewell GW, Md-Ibrahim MN, Reikine S, Sirago G, Unger LW, Iglesias-Romero AB, Ramshorn K, Haag LM, Saveljeva S, Ebel JF, Rosenstiel P, Kaneider NC, Lee JC, Lawley TD, Bradley A, Dougan G, Modis Y, Griffin JL, Kaser A Cell. 2020 Jan 23;180(2):278-295.e23. doi: 10.1016/j.cell.2019.12.017. PMID:31978345[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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