Crystal Structure of Yeast tRNA phe and General Structural Features of Other tRNAs

Abstract

Since the discovery of the “L-shaped” backbone structure of yeast tRNA phe in 1973, considerably more details are known for this tRNA structure in two different crystal forms. Examination of structural details of this tRNA allows one to make the following general conclusions. First, all free tRNAs are likely to assume the overall shape of an “L” with each arm being approximately 60 A long and 20 A thick. Second, most of the conserved and semiconserved bases in all tRNAs are involved in forming tertiary hydrogen bonds essential for maintaining the L-shaped three-dimensional structure. There are several recent review articles on the three-dimensional structure of yeast tRNA phe emphasizing different aspects (Sigler 1975; Rich and RajBhandary 1976; Clark 1977; Kim 1976, 1978). In this paper, I will briefly summarize the structural features and relative confidence levels with which they have been determined by X-ray crystallographic technique from four different research groups (Ladner et al. 1975; Quigley et al. 1975; Sussman and Kim 1976; Stout et al. 1976; and subsequent works cited in Kim 1978) and point out the structural features of functional interest based on the most recent available results (Jack et al. 1976Jack et al. 1977; Holbrook et al. 1977, 1978; Quigley et al. 1978; Sussman et al. 1978). To avoid lengthy and often confusing descriptions, many structural features are represented with figures. CRYSTAL STRUCTURE OF YEAST tRNA phe Overall Structure The crystal structure of yeast tRNA phe has an overall L shape (Kim et al. 1973), with the polynucleotide backbone of this model folded...