title: Letter: Evolution of tRNA and origin of the two positional isomers of zeatin.
mesh_terms: D005075:Biological Evolution; D008968:Molecular Conformation; D010944:Plants; D011687:Purines; D012343:RNA, Transfer; D015026:Zeatin
chemical_list: D011687:Purines; D015026:Zeatin; D012343:RNA, Transfer