title: X-ray crystallographic analysis of the structural basis for the interaction of pokeweed antiviral protein with guanine residues of ribosomal RNA.
abstract: Pokeweed antiviral protein (PAP) is a ribosome-inactivating protein (RIP), which enzymatically removes a single adenine base from a conserved, surface exposed loop sequence of ribosomal rRNA. We now present unprecedented experimental evidence that PAP can release not only adenine but guanine as well from Escherichia coli rRNA, albeit at a rate 20 times slower than for adenine. We also report X-ray structure analysis and supporting modeling studies for the interactions of PAP with guanine. Our modeling studies indicated that PAP can accommodate a guanine base in the active site pocket without large conformational changes. This prediction was experimentally confirmed, since a guanine base was visible in the active site pocket of the crystal structure of the PAP-guanine complex.
authors.affiliation: Department of Structural Biology, Hughes Institute, Roseville, Minnesota 55113, USA. igor@ih.org
authors.forename: I V
authors.initials: IV
authors.lastname: Kurinov
authors.forename: F
authors.initials: F
authors.lastname: Rajamohan
authors.forename: T K
authors.initials: TK
authors.lastname: Venkatachalam
authors.forename: F M
authors.initials: FM
authors.lastname: Uckun
mesh_terms: D000998:Antiviral Agents / Q000737:chemistry; D001665:Binding Sites; D018360:Crystallography, X-Ray / Q000379:methods; D004926:Escherichia coli / Q000235:genetics; D006147:Guanine; D006860:Hydrogen Bonding; D008024:Ligands; D008958:Models, Molecular; D009699:N-Glycosyl Hydrolases; D009690:Nucleic Acid Conformation; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D012335:RNA, Ribosomal / Q000737:chemistry* / Q000378:metabolism; D054789:Ribosome Inactivating Proteins, Type 1
chemical_list: D000998:Antiviral Agents; D008024:Ligands; D010940:Plant Proteins; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D054789:Ribosome Inactivating Proteins, Type 1; D006147:Guanine; D009699:N-Glycosyl Hydrolases; C024275:pokeweed antiviral protein