title: Photoreaction of 8-methoxypsoralen with yeast-tRNAPhe. Identification of the major reaction sites.
abstract: Yeast tRNAPhe was photoreacted with [3H]8-methoxypsoralen and the product was digested with ribonuclease T1, ribonuclease A or a combination of the two or cleaved with sodium borohydride/aniline. The oligonucleotides from these digestions were analyzed by polyacrylamide gel electrophoresis or high-pressure liquid chromatography and the psoralen-containing fragments were identified. The results indicate that one major and two minor photoreaction sites for 8-methoxypsoralen exist in yeast tRNAPhe. The major site (containing about 55% of the label) was determined as U50 in the T psi arm of the tRNA molecule while the minor sites were assigned to U59 (30% of the label) and C70 (15%) respectively. Our results suggest that psoralens may be used as photoprobes for studying conformational changes in tRNA molecules.
mesh_terms: D000814:Aniline Compounds; D001665:Binding Sites; D001894:Borohydrides; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006868:Hydrolysis; D008730:Methoxsalen / Q000528:radiation effects*; D009690:Nucleic Acid Conformation; D010777:Photochemistry; D012346:RNA, Transfer, Amino Acyl / Q000528:radiation effects*; D006163:Ribonuclease T1; D012259:Ribonuclease, Pancreatic; D012441:Saccharomyces cerevisiae / Q000235:genetics
chemical_list: D000814:Aniline Compounds; D001894:Borohydrides; D012346:RNA, Transfer, Amino Acyl; C025364:sodium borohydride; D006163:Ribonuclease T1; D012259:Ribonuclease, Pancreatic; C023650:aniline; D008730:Methoxsalen