Promotes tail assembly by creating a scaffold for the tail tube proteins. Tail assembly proteins G and GT probably wrap the linear tape measure protein to create a tail assembly scaffold. This allows the polymerization of the tail tube protein, during which G and GT are released, therefore they are absent in the mature virion. The tail assembly protein GT is produced by a rare -1 ribosomal frameshift. The ratio of translated G/GT is about 20, and this ratio is important for proper tail assembly. Interacts (via C-terminus) with tail tube protein. Interacts (via N-terminus) with the tail assembly protein G and the tape measure protein. The tail assembly protein GT is produced by a rare -1 ribosomal frameshift. This expression strategy assures a fixed ration of G/GT. Frameshifted product of the GT gene, representing 3-4% of the translated protein. Belongs to the lambda-like tail assembly protein family.