Abstract
Elongation factor Tu (EF-Tu) is a G-protein which, in its active GTP conformation, protects and carries aminoacylated tRNAs (aa-tRNAs) to the ribosome during protein biosynthesis. EF-Tu consists of three structural domains of which the N-terminal domain consists of two special regions (switch I and switch II) which are structurally dependent on the type of the bound nucleotide. Structural studies of the complete functional cycle of EF-Tu reveal that it undergoes rather spectacular conformational changes when activated from the EF-Tu.GDP form to the EF-Tu.GTP form. In its active form, EF-Tu.GTP without much further structural change interacts with aa-tRNAs in the so-called ternary complex. The conformational changes of EF-Tu involve rearrangements of the secondary structures of both the switch I and switch II regions. As the switch II region forms part of the interface between domains 1 and 3, its structural rearrangement results in a very large change of the position of domain 1 relative to domains 2 and 3. The overall shape of the ternary complex is surprisingly similar to the overall shape of elongation factor G (EF-G). Thus, three domains of the protein EF-G seem to mimic the tRNA part of the ternary complex. This macromolecular mimicry has profound implications for the function of the elongation factors on the ribosome.
| Original language | English |
|---|---|
| Journal | Structure |
| Volume | 2 |
| Issue | 3 |
| Pages (from-to) | S7-11 |
| ISSN | 0969-2126 |
| Publication status | Published - 1997 |
Keywords
- Amino Acid Sequence
- Guanosine Diphosphate
- Guanosine Triphosphate
- Macromolecular Substances
- Models, Molecular
- Molecular Mimicry
- Molecular Sequence Data
- Peptide Chain Elongation, Translational
- Peptide Elongation Factor Tu
- Protein Biosynthesis
- Protein Folding
- Protein Structure, Secondary
- Sequence Homology, Amino Acid