6f3n

Crystal structure of S-adenosyl-L-homocysteine hydrolase from Pseudomonas aeruginosa cocrystallized with SAH in the presence of K+ and Zn2+ cations

spinqualitylabelsall models 6f3n, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6f3n is a 4 chain structure with sequence from Pseudomonas aeruginosa PAO1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.85Å Ligands: ADN, GOL, K, NAD, PO4, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SAHH_PSEAE May play a key role in the regulation of the intracellular concentration of adenosylhomocysteine. Publication Abstract from PubMed S-adenosyl-L-homocysteine hydrolase from Pseudomonas aeruginosa (PaSAHase) coordinates one K(+) ion and one Zn(2+) ion in the substrate binding area. The cations affect the enzymatic activity and substrate binding but the molecular mechanisms of their action are unknown. Enzymatic and isothermal titration calorimetry studies demonstrated that the K(+) ions stimulate the highest activity and strongest ligand binding in comparison to other alkali cations, while the Zn(2+) ions inhibit the enzyme activity. PaSAHase was crystallized in the presence of adenine nucleosides and K(+) or Rb(+) ions. The crystal structures show that the alkali ion is coordinated in close proximity of the purine ring and a (23)Na NMR study showed that the monovalent cation coordination site is formed upon ligand binding. The cation, bound in the area of a molecular hinge, orders and accurately positions the amide group of Q65 residue to allow its interaction with the ligand. Moreover, binding of potassium is required to enable unique dynamic properties of the enzyme that ensure its maximum catalytic activity. The Zn(2+) ion is bound in the area of a molecular gate that regulates access to the active site. Zn(2+) coordination switches the gate to a shut state and arrests the enzyme in its closed, inactive conformation. Metal-cation regulation of enzyme dynamics is a key factor influencing the activity of S-adenosyl-L-homocysteine hydrolase from Pseudomonas aeruginosa.,Czyrko J, Sliwiak J, Imiolczyk B, Gdaniec Z, Jaskolski M, Brzezinski K Sci Rep. 2018 Jul 27;8(1):11334. doi: 10.1038/s41598-018-29535-y. PMID:30054521 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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