Chemical Modification of Yeast Alanine-tRNA with a Radioactive Carbodiimide

Abstract
Yeast alanine-tRNA was reacted with 1-cyclohexyl-3-[2-morpholinyl-(4)-ethyl] carbodiimide 14C-methoiodide in the presence of magnesium ion. The carbodiimide formed addition products with bases in the sequences ψpGp, UpCp and UpUpIpGpCp. The expected bases in the sequence TpψpCpGpApUp did not react, although this region is postulated to be in a loop that is not hydrogen-bonded. The capacity of the alanine-tRNA to accept amino acids decreased after reaction with the carbodiimide.