6vsu

Arginase from Arabidopsis thaliana in Complex with Ornithine

spinqualitylabelsall models 6vsu, resolution 2.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6vsu is a 24 chain structure with sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.25Å Ligands: GOL, MN, NA, ORN, PEG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ARGI1_ARATH Catalyzes the hydrolysis of L-arginine to urea and L-ornithine. The latter can be utilized in the urea cycle or as a precursor for the synthesis of both polyamines and proline. Possesses agmatinase activity. Catalyzes the formation of putrescine from agmatine (PubMed:28716421).[UniProtKB:P05089] Publication Abstract from PubMed Arginine acts as a precursor of polyamines in plants in two known pathways, agmatine and ornithine routes. It is decarboxylated to agmatine by arginine decarboxylase, and then transformed to putrescine by the consecutive action of agmatine iminohydrolase and N-carbamoylputrescine amidohydrolase. Alternatively, it can be hydrolyzed to ornithine by arginase and then decarboxylated by ornithine decarboxylase to putrescine. Some plants lack a functional ornithine pathway, but all have one or two arginases that can have dual cellular localization, in mitochondria and plastids. It was recently shown that arginases from Arabidopsis thaliana and soybean act also as agmatinases, thus they can produce putrescine directly from agmatine. Therefore, arginase (together with arginine decarboxylase) can complement putrescine production in plastids, providing a third polyamine biosynthesis pathway in plants. Phylogenetic analysis suggests that arginases, highly conserved in the plant kingdom, create the only group of enzymes recognized in the family of ureohydrolases in plants. Arginases are metalloenzymes with binuclear manganese cluster in the active site. In this work, two arginases from A. thaliana and Medicago truncatula are structurally characterized and their binding properties are discussed. Crystal structures with bound ornithine show that plant hexameric arginases engage a long loop from the neighboring subunit to stabilize alpha-amino and carboxyl groups of the ligand. This unique ligand binding mode is unobserved in arginases from other domains of life. Structural analysis shows that substrate binding by residues from two neighboring subunits might also characterize some prokaryotic agmatinases. This feature of plant arginases is most likely the determinant of their ability to recognize not only arginine but also agmatine as their substrates, thus, to act as arginase and agmatinase. The Neighboring Subunit Is Engaged to Stabilize the Substrate in the Active Site of Plant Arginases.,Sekula B Front Plant Sci. 2020 Jul 10;11:987. doi: 10.3389/fpls.2020.00987. eCollection, 2020. PMID:32754173 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Arginase 3D structures

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