4i47

Crystal structure of the Ribosome inactivating protein complexed with methylated guanine

spinqualitylabelsall models 4i47, resolution 2.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4i47 is a 1 chain structure with sequence from Momordica balsamina. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MY6, NAG Related: 3s9q Activity: rRNA N-glycosylase, with EC number 3.2.2.22 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed This is the first structural evidence of recognition of mRNA cap structures by a ribosome inactivating protein. It is well known that a unique cap structure is formed at the 5' end of mRNA for carrying out various processes including mRNA maturation, translation initiation, and RNA turnover. The binding studies and crystal structure determinations of type 1 ribosome inactivating protein (RIP-1) from Momordica balsamina (MbRIP-1) were carried out with mRNA cap structures including (i) N7-methyl guanine (m7G), (ii) N7-methyl guanosine diphosphate (m7GDP), and (iii) N7-methyl guanosine triphosphate (m7GTP). These compounds showed affinities to MbRIP-1 at nanomolar concentrations. The structure determinations of the complexes of MbRIP-1 with m7G, m7GDP, and m7GTP at 2.65, 1.77, and 1.75 A resolutions revealed that all the three compounds bound to MbRIP-1 in the substrate binding site at the positions which are slightly shifted towards Glu85 as compared to those of rRNA substrates. In this position, Glu85 forms several hydrogen bonds with guanine moiety while N-7 methyl group forms van der Waals contacts. However, the guanine rings are poorly stacked in these complexes. Thus, the mode of binding by MbRIP-1 to mRNA cap structures is different which results in the inhibition of depurination. Since some viruses are known to exploit the capping property of the host, this action of MbRIP-1 may have implications for the antiviral activity of this protein in vivo. The understanding of the mode of binding of MbRIP-1 to cap structures may also assist in the design of anti-viral agents. First structural evidence of sequestration of mRNA cap structures by type 1 ribosome inactivating protein from Momordica balsamina.,Kushwaha GS, Yamini S, Kumar M, Sinha M, Kaur P, Sharma S, Singh TP Proteins. 2013 May;81(5):896-905. doi: 10.1002/prot.24248. Epub 2013 Feb 25. PMID:23280611 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosome inactivating protein

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