Open AccessDifferent conformations of tRNA in the ribosomal P‐site and A‐site
Author(s) -
JØRGENSEN Tony,
SIBOSKA Gunhild E.,
WIKMAN Friedrik P.,
CLARK Brian F. C.
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb09287.x
Subject(s) - transfer rna , rnase p , footprinting , p site , ribosomal rna , t arm , a site , biology , binding site , ribosomal protein , biochemistry , ribosome , chemistry , stereochemistry , rna , base sequence , gene
Footprinting studies involving radioactively end‐labelled tRNA species bound at either the ribosomal P‐or A‐site have yielded information that the tRNA's conformation is different in the two sites. Appropriate controls showed the relevance of using poly(U)‐directed tRNA Phe binding in the P‐site and Phe‐tRNA Phe in the A‐site. Digestion of the tRNA species was effected by RNases T 1 , T 2 and cobra venom RNase. Experiments were performed with tRNAs 32 P‐labelled at either end to establish positions of primary cuts more confidently. In addition to the common protection of the aminoacyl‐stem and anticodon‐arm, footprinting experiments revealed striking differences in the accessibility of the T‐and d ‐loops of tRNAs bound in the P‐and A‐sites. We observed a more open structure for the tRNA in the A‐site. These results are consistent with a dynamic structure of tRNA during the translocation step of protein biosynthesis.