Studies on bacteriophage fd DNA: IV. The sequence of messenger RNA for the major coat protein gene

Abstract

One of the RNA species transcribed in vitro on phage fd replicative form DNA is initiated at a site preceding the major coat protein gene and terminated immediately after this gene. The total sequence of this RNA seecies was determined. The transcript was 369 bases long, and contained the sequence identical to the ribosome-binding site for phage f1 coat protein gene (Pieczenik et al., 1974) at positions 88 to 119 and the sequence for coat protein at positions 175 to 324. The coat protein sequence was immediately followed by two termination codons UGA and UAA. The AUG codon appeared at the fifth and 23rd tripletframe upstream from the codon for the first amino acid (Ala) of coat protein. The latter AUG codon was located in the middle of the ribosome-binding site. The result strongly suggests that coat protein is formed from a precursor containing 23 extra amino acid residues at the N-terminus. The transcript was usually terminated with a sequence of eight U residues. It was also noted that there is a region of strong secondary structure near the 3′-end.