tRNA Mimicry and its Role in Protein Synthesis
The interaction of so many different factors with the translation machinery has postulated many to believe that there must be some common elements within these translation factors. Nakamura and colleagues believe that there exists a similarity in structure between translation factors and tRNA. This molecular mimicry between protein factors and nucleic acids can be observed from the high sequence homology between domain III of eIF-2 attached to eIF-1, which can form a complex that 'mimics' the anticodon domain of the A-site bound aminoacyl-tRNA (Nakamura et al., 1998).
By allowing translation factors to mimic tRNA structure, the eIF1-2 complex is capable of locating the initiator tRNA to the ribosomal P-site and preventing its interactions with the A-site. Nakamura and colleagues presented this analogy for ribosomal A-site occupancy, as a master key, the key being mimicking the structure of tRNA. This master key can 'unlock' the ribosome and mediate initiation and subsequent elongation and termination. Elongation and termination factors also incorporate this tRNA mimicry trait to carry out their functions (Nakamura et al., 1998). This system of mimicry, between protein and tRNA, is believed to be capable of satisfying the requirement of structure to function relationships within protein synthesis.