Enzymatic aminoacylation of single-stranded RNA with an RNA cofactor.
A chemically synthesized single-stranded ribonucleotide tridecamer derived from the 3' end of Escherichia coli alanine tRNA can be charged with alanine in the presence of short complementary RNA oligonucleotides that form duplexes with the 3' fragment. Complementary 5' oligomers of 9, 8, 6, and 4 nucleotides all confer charging of the 3' fragment. Furthermore, in the presence of limiting 5' oligomer, greater than stoichiometric amounts of the single-stranded 3' acceptor fragment can be aminoacylated. This is due to a reiterative process of transient duplex formation followed by charging, dissociation of the 5' oligomer, and then rebinding to an uncharged single-stranded ribotridecamer so as to create another transient duplex substrate. Thus, a short RNA oligomer serves as a cofactor for a charging enzyme, and it thereby makes possible the aminoacylation of single-stranded RNA. These results expand possibilities for flexible routes to the development of early charging and coding systems.
Musier-Forsyth
K
K
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Scaringe
S
S
Usman
N
N
Schimmel
P
P
D000412:Alanine-tRNA Ligase / Q000378:metabolism*; D001482:Base Composition; D001483:Base Sequence; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012344:RNA, Transfer, Ala / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D046911:Macromolecular Substances; D012344:RNA, Transfer, Ala; D000412:Alanine-tRNA Ligase