Triple aminoacylation specificity of a chimerized transfer RNA.
We report here the rational design and construction of a chimerized transfer RNA with tripartite aminoacylation specificity. A yeast aspartic acid specific tRNA was transformed into a highly efficient acceptor of alanine and phenylalanine and a moderate acceptor of valine. The transformation was guided by available knowledge of the requirements for aminoacylation by each of the three amino acids and was achieved by iterative changes in the local sequence context and the structural framework of the variable loop and the two variable regions of the dihydrouridine loop. The changes introduced to confer efficient acceptance of the three amino acids eliminate aminoacylation with aspartate. The interplay of determinants and antideterminants for different specific aminoacylations, and the constraints imposed by the structural framework, suggest that a tRNA with an appreciable capacity for more than three efficient aminoacylations may be inherently difficult to achieve.
Frugier
M
M
Unité Propre de Recherche Structure des Macromolécules Biologiques et Mécanismes de Reconnaissance, Centre National de la Recherche Scientifique, Strasbourg, France.
Florentz
C
C
Schimmel
P
P
Giegé
R
R
D000215:Acylation; D000409:Alanine / Q000378:metabolism; D001483:Base Sequence; D002678:Chimera; D004926:Escherichia coli / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010649:Phenylalanine / Q000378:metabolism; D012349:RNA, Transfer, Asp / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D014633:Valine / Q000378:metabolism
D012349:RNA, Transfer, Asp; D010649:Phenylalanine; D014633:Valine; D000409:Alanine