Biomedical subjects

K Musier-Forsyth

Publications and source records attributed to K Musier-Forsyth.

39 records · Page 3Linked to original sources

PubMed1992

Small RNA helices as substrates for aminoacylation and their relationship to charging of transfer RNAs.

RNA microhelices that reconstruct the acceptor stems of transfer RNAs can be aminoacylated. The anticodon-independent aminoacylation is sequence-specific and suggests a relationship between amino acids and nucleotide sequences which is different from that of the classical genetic code. The specific aminoacylation of RNA microhelices also suggests a highly differentiated adaptation of the structures of aminoacyl-tRNA synthetases to sequences in the acceptor stems of transfer RNAs.

Amino Acid Sequence↗

PubMed1991

Specificity for aminoacylation of an RNA helix: an unpaired, exocyclic amino group in the minor groove.

An acceptor stem G3.U70 base pair is a major determinant of the identity of an alanine transfer RNA. Hairpin helices and RNA duplexes consisting of complementary single strands are aminoacylated with alanine if they contain G3.U70. Chemical synthesis of RNA duplexes enabled the introduction of base analogs that tested the role of specific functional groups in the major and minor grooves of the RNA helix. The results of these experiments indicate that an unpaired guanine 2-amino group at a specific position in the minor groove of an RNA helix marks a molecule for aminoacylation with alanine.

Acylation↗

PubMed1991

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.

Alanine-tRNA Ligase↗