The Structure, Conformation, and Interaction of tRNA

Abstract

tRNA molecules are perhaps the smallest polynucleotides (75–93 residues) that possess profound biological functions. The most important function of tRNAs is their role in protein synthesis. Information on the three-dimensional structure of tRNA is of paramount importance for an understanding of the molecular basis of this and the other functions of tRNAs. The structure of yeast tRNA phe has been determined in both the orthorhombic and monoclinic forms (Kim et al. 1974; Robertus et al. 1974; Quigley and Rich 1975; Jack et al. 1976; Stout et al. 1976, 1978) using the single crystal X-ray diffraction technique. The structure of the monoclinic form was determined in our laboratory in late 1974 at low resolution and the complete structure describing the coordinates and the stereochemistry of the nucleotide and internucleotide phosphoesters were reported in 1976 (Stout et al. 1976Stout et al. 1978; Sundaralingam et al. 1976; Sundaralingam 1978). Further details of the earlier structural work on tRNAs may be found in a recent review by Goddard (1978), as well as in the Proceedings of the Steenbock Symposium (Sundaralingam and Rao 1975). In this paper the salient stereochemical features of yeast tRNA phe in relation to the established principles of the stereochemistry of nucleic acids and their constituents are presented.1 THREE-DIMENSIONAL STRUCTURE Backbone Fold The folding of the polynucleotide backbone chain in tRNA phe is shown in Figure 1 and stereoviews of the complete and partial structures in Figure 2. The helical segments predicted by the Holley cloverleaf diagram are preserved in their entirety. The acceptor (A)...