1qcg

LOW TEMPERATURE STRUCTURE OF POKEWEED ANTIVIRAL PROTEIN

spinqualitylabelsall models 1qcg, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1qcg is a 2 chain structure with sequence from Phytolacca americana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1qci, 1qcj Resources: FirstGlance, OCA, RCSB, PDBsum Function [RIP1_PHYAM] Inhibits viral infection of plants, and protein synthesis in vitro. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The pokeweed antiviral protein (PAP) belongs to a family of ribosome-inactivating proteins (RIP), which depurinate ribosomal RNA through their site-specific N-glycosidase activity. We report low temperature, three-dimensional structures of PAP co-crystallized with adenyl-guanosine (ApG) and adenyl-cytosine-cytosine (ApCpC). Crystal structures of 2.0-2.1 A resolution revealed that both ApG or ApCpC nucleotides are cleaved by PAP, leaving only the adenine base clearly visible in the active site pocket of PAP. ApCpC does not resemble any known natural substrate for any ribosome-inactivating proteins and its cleavage by PAP provides unprecedented evidence for a broad spectrum N-glycosidase activity of PAP toward adenine-containing single stranded RNA. We also report the analysis of a 2.1 A crystal structure of PAP complexed with the RIP inhibitor pteoric acid. The pterin ring is strongly bound in the active site, forming four hydrogen bonds with active site residues and one hydrogen bond with the coordinated water molecule. The second 180 degrees rotation conformation of pterin ring can form only three hydrogen bonds in the active site and is less energetically favorable. The benzoate moiety is parallel to the protein surface of PAP and forms only one hydrogen bond with the guanido group of Arg135. X-ray crystallographic analysis of the structural basis for the interactions of pokeweed antiviral protein with its active site inhibitor and ribosomal RNA substrate analogs.,Kurinov IV, Myers DE, Irvin JD, Uckun FM Protein Sci. 1999 Sep;8(9):1765-72. PMID:10493577 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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