3anx | pdb_00003anx

Crystal structure of triamine/agmatine aminopropyltransferase (SPEE) from thermus thermophilus, complexed with MTA

spinqualitylabelsall models 3anx, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3anx is a 2 chain structure with sequence from Thermus thermophilus HB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.5Å Ligands: MTA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SPEE_THET8 Catalyzes the production of spermidine from putrescine and decarboxylated S-adenosylmethionine (dcSAM), which serves as an aminopropyl donor. Has broad substrate specificity. Is also active with agmatine and norspermidine. Has lower activity with homospermidine, mitsubishine and thermine. Publication Abstract from PubMed To maintain functional conformations of DNA and RNA in high-temperature environments, an extremely thermophilic bacterium, Thermus thermophilus, employs a unique polyamine biosynthetic pathway and produces more than 16 types of polyamines. In the thermophile genome, only one spermidine synthase homolog (SpeE) was found and it was shown to be a key enzyme in the pathway. The catalytic assay of the purified enzyme revealed that it utilizes triamines (norspermidine and spermidine) and agmatine as acceptors in its aminopropyl transfer reaction; therefore, the enzyme was denoted as a triamine/agmatine aminopropyltransferase (TAAPT). We determined the crystal structures of the enzyme complexed with and without the aminopropyl group donor S-adenosylmethionine. Despite sequence and structural similarity with spermidine synthases from other organisms, a novel C-terminal beta-sheet and differences in the catalytic site were observed. The C-terminal module interacts with the gatekeeping loop and fixes the open conformation of the loop to recognize larger polyamine substrates such as agmatine and spermidine. Additional computational docking studies suggest that the structural differences of the catalytic site also contribute to recognition of the aminopropyl/aminobutyl or guanidium moiety of the substrates of TAAPT. These results explain in part the extraordinarily diverse polyamine spectrum found in T. thermophilus. Crystal structures and enzymatic properties of a triamine/agmatine aminopropyltransferase from Thermus thermophilus.,Ohnuma M, Ganbe T, Terui Y, Niitsu M, Sato T, Tanaka N, Tamakoshi M, Samejima K, Kumasaka T, Oshima T J Mol Biol. 2011 May 20;408(5):971-86. Epub 2011 Mar 31. PMID:21458463 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Spermidine synthase 3D structures

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