Properties of Bacteriophage T4 Baseplate Protein Encoded by Gene 8

Gene product 8 (gp8, 344 amino acids per monomer) of bacteriophage T4 is one of the baseplate structural proteins. We constructed an expression vector of gp8 and developed a method for purification of recombinant protein. CD spectroscopy showed that gp8 is an / type structural protein. Its polypeptide chain consists of nearly 40% -structure and 15% -helix. These data agree with results of prediction of secondary structure based on the amino acid sequence of the protein. The sedimentation coefficient under standard conditions (S_20,w) is 4.6S. Analytical ultracentrifugation results demonstrated that gp8 in solution has two types of oligomers—dimer and tetramer. The tetramer of gp8 may be included in the wedge (1/6 of the baseplate), and the dimer may be an intermediate product of association.