The Structure of Baker’s Yeast tRNAGly: A Second tRNA Conformation

Abstract

Yeast tRNA^Phe is the first nucleic acid whose structure has been determined in atomic detail (Quigley et al. 1975; Sussman and Kim 1976; Jack et al. 1976). The crystal structure of this molecule contains the double-helical regions anticipated by the general cloverleaf scheme derived from tRNA sequence information (Holley et al. 1965; Zachau et al. 1966; RajBhandary et al. 1967) and from spectroscopic studies (Fresco et al. 1964; Reid and Robillard 1975). In addition, the tRNA^Phe tertiary structure observed in the two crystal forms appears to depend for its integrity upon hydrogen bonds and, to a lesser extent, upon stacking interactions between bases from parts of the molecule that are remote in the sequence (Klug et al. 1974a; Kim et al. 1974). The conservation of these interacting bases in the available tRNA sequences supports the notion that all tRNAs have similar structures under physiological solvent and temperature conditions, as was first deduced from consideration of their common functions, narrow size distribution, and very similar hydro-dynamic properties in the native state (Lindahl et al. 1965; Fresco et al. 1967). Furthermore, chemical modification (Robertus et al. 1974), nuclear magnetic resonance (Shulman et al. 1973; Reid and Robillard 1975), and relaxation kinetic studies (Riesner et al. 1973) on several tRNAs are consistent with the general features revealed by the crystal structure, so that it seems unlikely that crystallization has selected out a particular minor conformer of tRNA^Phe.

Although the weight of circumstantial evidence supports a common, general structure for all tRNA molecules, small...