3mx8

Crystal structure of ribonuclease A tandem enzymes and their interaction with the cytosolic ribonuclease inhibitor

spinqualitylabelsall models 3mx8, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3mx8 is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, SO4 Related: 1r3m, 1bsr, 1a2w, 7rsa, 1srn, 3mwq, 3mwr Activity: Pancreatic ribonuclease, with EC number 3.1.27.5 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [RNAS1_BOVIN] Endonuclease that catalyzes the cleavage of RNA on the 3' side of pyrimidine nucleotides. Acts on single stranded and double stranded RNA. Publication Abstract from PubMed Because of their ability to degrade RNA, RNases are potent cytotoxins. The cytotoxic activity of most members of the RNase A superfamily, however, is abolished by the cytosolic ribonuclease inhibitor (RI). RNase A tandem enzymes, in which two RNase A molecules are artificially connected by a peptide linker, and thus have a pseudodimeric structure, exhibit remarkable cytotoxic activity. In vitro, however, these enzymes are still inhibited by RI. Here, we present the crystal structures of three tandem enzymes with the linker sequences GPPG, SGSGSG, and SGRSGRSG, which allowed us to analyze the mode of binding of RI to the RNase A tandem enzymes. Modeling studies with the crystal structures of the RI-RNase A complex and the SGRSGRSG-RNase A tandem enzyme as templates suggested a 1 : 1 binding stoichiometry for the RI-RNase A tandem enzyme complex, with binding of the RI molecule to the N-terminal RNase A entity. These results were experimentally verified by analytical ultracentrifugation, quantitative electrophoresis, and proteolysis studies with trypsin. As other dimeric RNases, which are comparably cytotoxic, either evade RI binding or potentially even bind two RI molecules, inactivation by RI cannot be the crucial limitation to the cytotoxicity of dimeric RNases. Crystal structure of RNase A tandem enzymes and their interaction with the cytosolic ribonuclease inhibitor.,Arnold U, Leich F, Neumann P, Lilie H, Ulbrich-Hofmann R FEBS J. 2011 Jan;278(2):331-40. doi: 10.1111/j.1742-4658.2010.07957.x., Epub 2010 Dec 6. PMID:21134128 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Temp

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