Rapid fold and structure determination of the archaeal translation elongation factor 1 beta from Methanobacterium thermoautotrophicum

The tertiary fold of the elongation factor, aEF-1 beta, from Methanobacteri um thermoautotrophicum was determined in a high-throughput fashion using a minimal set of NMR experiments. NMR secondary structure prediction, deuteri um exchange experiments and the analysis of chemical shift perturbations we re combined to identify the protein fold as an alpha-beta sandwich typical of many RNA binding proteins including EF-G. Following resolution of the te rtiary fold, a high resolution structure of aEF-1 beta was determined using heteronuclear and homonuclear NMR experiments and a semi-automated NOESY a ssignment strategy. Analysis of the aEF-1 beta structure revealed close sim ilarity to its human analogue, eEF-1 beta. In agreement with studies on EF- Ts and human EF-1 beta, a functional mechanism for nucleotide exchange is p roposed wherein Phe46 on an exposed loop acts as a lever to eject GDP from the associated elongation factor G-protein, aEF-1 alpha. aEF-1 beta was als o found to bind calcium in the groove between helix alpha 2 and strand beta 4. This novel feature was not observed previously and may serve a structur al function related to protein stability or may play a functional role in a rchaeal protein translation.