Gene 67, a new,essential bacteriophage T4 head gene codes for a prehead core component,PIP: I. Genetic mapping and DNA sequence

A new bacteriophage T4 gene has been identified and located between genes 20 and 21. This gene codes for PIP, a component of the prehead core and precursor to one of the two species of small, acidic peptides found inside the mature phage head. We have determined the DNA sequence of the gene. Both the DNA sequence and the amino acid sequence derived from it are unusual, and between them explain why suppressor-sensitive mutations in the gene have not been found using classical mutagenesis. The codon usage in this gene is highly non-random. In the accompanying paper we show that PIP is essential for T4 growth and assign its gene a number. 67, to indicate that fact.