Evidence of interactions between Gp27 and Gp28 constituents of the central part of bacteriophage T4 baseplate.

The central part of the bacteriophage T4 baseplate consists of several proteins. However, for a number of the constituents the manner of incorporation are not convincingly established. Recently, we have presented evidence that gp28 is the structural component of the central part of the baseplate, which possesses a hydrophobic region and is membrane bound [Nieradko et al., 1998]. By utilizing extracts prepared from Escherichia coli cells that overexpressed genes 27 and 28 of phage T4, we proved that gp28 forms a complex with an another baseplate structural components: gp27. This complex was located in the membrane fraction. Its affinity to the inner membrane indicates that the identified complex may function as an initiator of the central hub assembly. It was subsequently established that these products interact in the ratio 1:1. We have also demonstrated that the particular components of the complex can be separated by action of SDS and to a lesser extent by Triton X-100.