Expression of genes 51, 27, 28 coding for proteins of the central part of bacteriophage T4 baseplate in the bacteriophage T7 promoter/RNA polymerase expression system.

A fragment of T4 DNA (XbaI-HindIII) comprising the genes 51, 27, 28, which encodes the central plug proteins was cloned into plasmid pT7-5 and p7-6 (T7 RNA polymerase expressing system). The examined genes were only overexpressed when the orientation of cloned DNA to promoter phi 10 was as follows: promoter phi 10 and genes 51, 27, 28. This was achieved when the fragment (XbaI-HindIII) was cloned into plasmid pT7-5. Gene 27 and 28 were overexpressed when the intact fragment (XbaI-HindIII) was used. The high rate of the synthesis of proteins 27 and/or 28 had a strong inhibitory effect on the level of synthesis of the product of gene 51. For the overexpression of gene 51 in this system a deletion derivate which was devoid of gene 28 and a larger fragment of gene 27 was prepared.