The three-dimensional folding of the tRNA-like structure of tobacco mosaic virus RNA. A new building principle applied twice

Abstract

The structure of the tRNA‐like 3′ terminus of tobacco mosaic virus (TMV) RNA has been studied. A 3′ ‐terminal fragment possessing the tRNA‐like properties was probed with chemical modification and enzymatic digestions. A model of the secondary structure is proposed for the last 105 nucleotides. The corresponding region of other tobamoviral RNAs can be folded in an identical secondary structure. A three‐dimensional model for the tRNA‐like structure is given which is compared with those proposed earlier for the tRNA‐like 3′ termini of turnip yellow mosaic virus (TYMV) RNA and brome mosaic virus (BMV) RNA. A new building principle which we discovered previously by studying the latter RNAs appears to be applied twice in the tRNA‐like structure of TMV RNA. The determination of the minimal length requirement for recognition of CTP, ATP:tRNA nucleotidyl‐transferase reveals a size of ˜100 nucleotides in agreement with the models proposed.