Tail assembly. The lambda tail is made of at least 6 proteins (U, V, J, H, Tfa, Stf) with another 7 required for assembly (I, M, L, K, G/T, Z). Assembly starts with protein J, which then, in a poorly characterized fashion, recruits proteins I, L, K, and G/T to add the tape measure protein H. G and G/T then leave the complex so that the main tail protein (V) can assemble on the J/H scaffold. Finally, U is added to the head-proximal end of the tail. Protein Z is required to connect the tail to the pre-assembled head. Protein H is cleaved between the action of U and Z . It remains unclear if proteins M and L are part of the final particle . Modified after .