Protein Chain-Initiating Methionine tRNAs in Chloroplasts and Cytoplasm of Wheat Leaves.
The role of methionine in protein chain initiation in wheat has been studied. Two chain-initiating methionine tRNAs have been found. One of these is located in the cytoplasm of the wheat cell. This methionyl-tRNA is not formylated by wheat extracts and appears to function in protein chain initiation in the cytoplasm without prior formylation. The other initiating tRNA is from chloroplasts. This methionyl-tRNA is formylated by a transformylase present in wheat extracts and functions in chain initiation in chloroplasts as formylmethionyl-tRNA.
SECTION OF BIOCHEMISTRY AND MOLECULAR BIOLOGY, CORNELL UNIVERSITY, ITHACA, NEW YORK 14850.
J P
JP
Leis
E B
EB
Keller