A common structural motif in elongation factor Ts and ribosomal protein L7/12 may be involved in the interaction with elongation factor Tu

Elongation factor (EF) Tu alternates between two interaction partners, EF-T s and the ribosome, during its functional cycle. On the ribosome, the inter action involves, among others, ribosomal protein L7/12. Here we compare EF- Ts and L7/12 with respect to the conservation of sequence and structure. Th ere is significant conservation of functionally important residues in the N -terminal domain of EF-Ts and in the C-terminal domain of L7/12. The struct ure alignment based on the crystal structures of the two domains suggests a high degree of similarity between the alphaA-betaD-alphaB motif in L7/12 a nd the h1-turn-h2 motif in EF-Ts which defines a common structural motif. T he motif is remarkably similar with respect to fold, bulkiness, and charge distribution of the solution surface, suggesting that it has a common funct ion in binding EF-Tu.