Likely key methionines (start codons) or their replacement amino acid are highlighted in green. doi:10.1371/journal.pone.0008390.g005 molecular mechanism of termination-reinitiation remains to be fully elucidated, however. Central to the discussion is the TURBS and in this context the purpose of the identified Motifs, the role (if any) of RNA secondary structure, and the functional requirement for translation through the TURBS.