The 3D structure of an encoded protein (red) is established and maintained by segments with specifically interacting domains that contain numerous amino acid co-locations (a-a’, b-b’, c-c’). Co-locating amino acids (X between their one letter names) are preferentially encoded by partially complementary codons, where the 1st and 3rd codon residues (pink letters connected by |) are complementary to one another (A-T or G-C), but the 2nd codon residues may be, but is not necessarily, complementary to each other. This rule is called the PROTEOMIC CODE. The complementary sites in nucleic acids define segments in the CDS (Nucleic Acid, blue, A-A’, B-B’, C-C’), which provide a 3D nucleic acid structure similar to the structure of the encoded protein. Codon amino acid interactions transfer the spatial information in CDS to proteins during translation. This process is called NUCLEIC ACID ASSISTED PROTEIN FOLDING [16,19,20].
