Bacteriophage tail components. 3. Use of synthetic pteroyl hexaglutamate for T4D tail plate assembly

The assembly of T4D tail plates occurring during in vitro complementation reactions was found to be stimulated by pteroyl hexaglutamate. Neither the pteroyl pentaglutamate nor the pteroyl heptaglutamate substituted for the hexaglutamate. A small stimulation of the rate and amount of T4D tail plate assembly was observed in untreated extracts. A greater stimulation occurred when activated charcoal-treated bacterial extracts were used. Charcoal treatment inhibited complementation only when no preformed tail plates were present in the extracts, and the inhibition was reversed by the addition of 9 x 10(-6)m chemically synthesized pteroyl hexaglutamate. The stimulation is apparently due to a requirement for the pteroyl hexaglutamate for tail plate assembly.