RNA codons and protein synthesis. Xi. Template activity of modified RNA codons.
Substituting 5'-, 2'-, 3'-terminal or 2'-internal ribose hydroxyls of oligonucleotides markedly affected their template activity in directing the binding of AA-sRNA to ribosomes. The relative template activity of oligo U preparations was as follows: p-5'-UpUpU > UpUpU > CH3O-p-5'-UpUpU > UpUpU-3'-p > UpUpU-3'-p-OCH3 > UpUpU-2',3'-cyclic phosphate. Trimers with (2'-5') phosphodiester linkages, (2'-5')-UpUpU and also (2'-5')-ApApA, did not serve as templates for phenylalanine- or lysine-sRNA, respectively. The relative template efficiency of oligo A preparations was as follows: p-5'-ApApA > ApApA > ApApA-3'-p > ApApA-2'-p. The hexamer, ApApApApApA was considerably more active as a template than the corresponding pentamer. These data indicate that two adjacent triplets are recognized by two AA-sRNA molecules bound to nearby ribosomal sites. A doublet with 5'-terminal phosphate, pUpC, served as a template for serine-sRNA, whereas a doublet without terminal phosphate, UpC, did not. Although the template efficiency of pUpC was lower than that of the triplet UpCpU the data show that serine-sRNA can recognize pUpC.
Rottman
F
F
Laboratory of Biochemical Genetics, National Heart Institute National Institutes of Health, Bethesda, Maryland, USA.
Nirenberg
M
M
D000227:Adenine Nucleotides / Q000737:chemistry / Q000235:genetics; D003062:Codon / Q000235:genetics*; D005815:Genetic Code; D009843:Oligoribonucleotides / Q000737:chemistry / Q000235:genetics; D010649:Phenylalanine / Q000235:genetics; D010710:Phosphates / Q000737:chemistry; D014176:Protein Biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D013698:Templates, Genetic
D000227:Adenine Nucleotides; D003062:Codon; D009843:Oligoribonucleotides; D010710:Phosphates; D012333:RNA, Messenger; C044861:uridylyl-(3'-5')-uridylyl-(3'-5')-3'-uridylic acid; D010649:Phenylalanine; C018832:adenylyl-(3'-5')-adenylyl-(3'-5')-adenosine