DNA sequence of the tail fibre genes 36 and 37 of bacteriophage T4

Abstract

We present here the DNA sequence of the tail fibre genes 36 and 37 of bacteriophage T4. The products of these genes form the major part of the 800 Å long distal half tail fibre of the phage. Restriction fragments of the DNA were subcloned in M13 phage and sequenced by the dideoxy sequencing method. A marker rescue technique was developed to allow rapid genetic identification of the particular T4 fragment carried by a given M13 clone, using the many T4 mutants available in the tail fibre region. This ensured little duplication in sequencing the M13 clones, and also allowed us to correlate the sequence with the genetic map. Predicted protein sequences are given for genes 36 and 37. Secondary structure prediction rules, when applied to the gene 37 protein, indicate the likely presence of regions of alternating β-strand and β-turn. This is consistent with previous structural analysis of the distal half fibre, which proposed an antiparallel β-structure running normal to the fibre axis, although the folding appears much less regular than anticipated.