Induced fitting between a complex of four nucleotides and the cognate amino acid.

The conformation of the hydrogen-bonded complex of a trinucleoside diphosphate (anticodon bases), a nucleic acid base (discriminator base), and an amino acid is investigated. This complex has been named C4N (complex of the four nucleotides) by one of the authors. Concerning the aminoacylation of tRNA and the genetic code, it has been proposed that C4N accepts the cognate protein amino acid by the lock-and-key relationship. The purpose of the calculation is to investigate the conformational and energetic properties of C4N from the energy minimum principle. The calculation is carried out by using the empirical potential functions. Glycine, glutamine, and valine are taken as typical cases. The formation energies are estimated. It is shown that some conformational changes are induced in the anticodon trinucleoside diphosphate by the binding of the discriminator base. Conformational changes of C4N and the amino acid are also induced by the binding of the amino acid to C4N.