Opal suppressor serine tRNAs from bovine liver form phosphoseryl-tRNA.

Abstract
An unusual minor species of bovine liver serine tRNA has previously been isolated, sequenced, and found to suppress the UGA termination codon in protein synthesis in vitro. This tRNA can be a substrate in a specific phosphorylation reaction in which phosphoseryl-tRNA is formed. Moreover, bovine liver contains a 2nd UGA suppressor serine tRNA .**GRAPHIC**. N is a modified nucleoside) which also forms phosphoseryl-tRNA. The nucleotide sequence and coding properties of .**GRAPHIC**. are presented.