title: P-site pairing subtleties revealed by the effects of different tRNAs on programmed translational bypassing where anticodon re-pairing to mRNA is separated from dissociation.
abstract: Programmed ribosomal bypassing occurs in decoding phage T4 gene 60 mRNA. Half the ribosomes bypass a 50 nucleotide gap between codons 46 and 47. Peptidyl-tRNA dissociates from the "take-off" GGA, codon 46, and re-pairs to mRNA at a matched GGA "landing site" codon directly 5' of codon 47 where translation resumes. The system described here allows the contribution of peptidyl-tRNA re-pairing to be measured independently of dissociation. The matched GGA codons have been replaced by 62 other matched codons, giving a wide range of bypassing efficiencies. Codons with G or C in either or both of the first two codon positions yielded high levels of bypassing. The results are compared with those from a complementary study of non-programmed bypassing, where the combined effects of peptidyl-tRNA dissociation and reassociation were measured. The wild-type, GGA, matched codons are the most efficient in their gene 60 context in contrast to the relatively low value in the non-programmed bypassing study.
authors.affiliation: Department of Human Genetics, University of Utah, 15N 2030E Rm7410, Salt Lake City, UT 84112-5330, USA.
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Bucklin
authors.forename: Norma M
authors.initials: NM
authors.lastname: Wills
authors.forename: Raymond F
authors.initials: RF
authors.lastname: Gesteland
authors.forename: John F
authors.initials: JF
authors.lastname: Atkins
mesh_terms: D000926:Anticodon / Q000235:genetics / Q000378:metabolism*; D001120:Arginine / Q000235:genetics; D001483:Base Sequence; D003062:Codon / Q000235:genetics / Q000378:metabolism; D003596:Cytosine / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D006147:Guanine / Q000378:metabolism; D007288:Inosine / Q000235:genetics; D009690:Nucleic Acid Conformation; D009704:Nucleoside Q / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism; D012694:Serine / Q000235:genetics; D014633:Valine / Q000235:genetics
chemical_list: D000926:Anticodon; D003062:Codon; D004269:DNA, Bacterial; D012333:RNA, Messenger; D012694:Serine; D009704:Nucleoside Q; D007288:Inosine; D006147:Guanine; D003596:Cytosine; D012343:RNA, Transfer; D001120:Arginine; D014633:Valine