Intermediate reactions in the binding of aminoacyl-transfer ribonucleic acid to rat liver ribosomes. The role of guanosine triphosphate.
1. Transferase I from rat liver binds relatively low quantities of GTP when incubated with this nucleotide in the absence of aminoacyl-tRNA. 2. Transferase I reacts with both aminoacyl-tRNA and GTP to form a relatively stable complex that is retained on cellulose nitrate filters. The ternary complex transferase I-aminoacyl-tRNA-GTP is also formed when the transferase I-aminoacyl-tRNA complex is incubated with GTP or during the incubation of the transferase I-GTP complex with aminoacyl-tRNA. Synthesis of this complex does not require the presence of Mg(2+). 3. In the presence of Mg(2+) the ternary complex becomes readily bound to ribosomes without requirements for any other cofactors. 4. An extensive cleavage of GTP takes place when aminoacyl-tRNA becomes bound to ribosomes. 5. The low interdependence of reactions leading to the formation of transferase I complexes with aminoacyl-tRNA and GTP indicates that the mechanisms of the binding reaction in mammalian systems may be different from those in bacterial cells.
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002247:Carbon Isotopes; D002482:Cellulose; D002850:Chromatography, Gel; D006160:Guanosine Triphosphate / Q000378:metabolism*; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism; D008274:Magnesium; D010649:Phenylalanine; D010759:Phosphorus Isotopes; D011485:Protein Binding; D012343:RNA, Transfer / Q000378:metabolism*; D051381:Rats; D012270:Ribosomes / Q000378:metabolism*; D014166:Transferases
D000596:Amino Acids; D002247:Carbon Isotopes; D010759:Phosphorus Isotopes; D010649:Phenylalanine; D006160:Guanosine Triphosphate; D002482:Cellulose; D012343:RNA, Transfer; D014166:Transferases; D008274:Magnesium