3one

Crystal structure of Lupinus luteus S-adenosyl-L-homocysteine hydrolase in complex with adenine

spinqualitylabelsall models 3one, resolution 1.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3one is a 2 chain structure with sequence from Lupinus luteus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.35Å Ligands: ADE, NA, NAD, TRS Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SAHH_LUPLU Adenosylhomocysteine is a competitive inhibitor of S-adenosyl-L-methionine-dependent methyl transferase reactions; therefore adenosylhomocysteinase may play a key role in the control of methylations via regulation of the intracellular concentration of adenosylhomocysteine (By similarity). Publication Abstract from PubMed S-Adenosyl-L-homocysteine hydrolase (SAHase) catalyzes the reversible breakdown of S-adenosyl-L-homocysteine (SAH) to adenosine and homocysteine. SAH is formed in methylation reactions that utilize S-adenosyl-L-methionine (SAM) as a methyl donor. By removing the SAH byproduct, SAHase serves as a major regulator of SAM-dependent biological methylation reactions. Here, the first crystal structure of SAHase of plant origin, that from the legume yellow lupin (LlSAHase), is presented. Structures have been determined at high resolution for three complexes of the enzyme: those with a reaction byproduct/substrate (adenosine), with its nonoxidizable analog (cordycepin) and with a product of inhibitor cleavage (adenine). In all three cases the enzyme has a closed conformation. A sodium cation is found near the active site, coordinated by residues from a conserved loop that hinges domain movement upon reactant binding. An insertion segment that is present in all plant SAHases is located near a substrate-pocket access channel and participates in its formation. In contrast to mammalian and bacterial SAHases, the channel is open when adenosine or cordycepin is bound and is closed in the adenine complex. In contrast to SAHases from other organisms, which are active as tetramers, the plant enzyme functions as a homodimer in solution. High-resolution structures of complexes of plant S-adenosyl-L-homocysteine hydrolase (Lupinus luteus).,Brzezinski K, Dauter Z, Jaskolski M Acta Crystallogr D Biol Crystallogr. 2012 Mar;68(Pt 3):218-31. Epub 2012 Feb 7. PMID:22349223 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also S-adenosylhomocysteine hydrolase

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