title: Specific protein-nucleic acid recognition in ribonuclease T1-2'-guanylic acid complex: an X-ray study.
abstract: RNase T1 is folded into an alpha-helix of 4.5 turns, covered by a four-strand antiparallel beta-sheet. Specific recognition of 2'-guanylic acid arises from hydrogen bonding between main chain peptide groups and the O-6 and N-1-H of guanine, as well as from stacking of Tyr 45 on guanine. At the active site, Glu 58, His 92 and Arg 77 are involved in phosphodiester hydrolysis.
mesh_terms: D000595:Amino Acid Sequence; D002384:Catalysis; D006150:Guanine Nucleotides / Q000378:metabolism*; D006157:Guanosine Monophosphate / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D006163:Ribonuclease T1 / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D014961:X-Ray Diffraction
chemical_list: D006150:Guanine Nucleotides; C026693:2'-guanylic acid; D006157:Guanosine Monophosphate; D012260:Ribonucleases; D006163:Ribonuclease T1