Molecule of the Month: Inteins
Inteins splice themselves out of larger protein chains
Inteins in the Lab
Large and Small
Exploring the Structure
Inteins (PDB entries 1jva and 1um2)
Two structures of the vacuolar ATPase intein show the protein before and after its splicing reaction. In both cases, a few of the catalytic amino acids were mutated to slow the reaction, so that the structure could solved. PDB entry 1jva (left) shows the intein (green) before the reaction, with small segments of the exteins (red and blue) attached. PDB entry 1um2 (right) is after the reaction, and the two exteins have been connected together. In the actual protein, the exteins are much larger, and when joined they form part of a large proton pump. To compare these two structures in more detail, click on the image for an interactive Jmol.
Topics for Further Discussion
- Structures are available for many different inteins. Can you find them in the PDB? Do the structures include the homing endonuclease, or are they mini-inteins?
- Do the structures include portions of the exteins? Why is it difficult to determine structures that include exteins?
Related PDB-101 Resources
- Browse Protein Synthesis
- Browse Nanotechnology
- S. Elleuche and S. Poggeler (2010) Inteins, valuable genetic elements in molecular biology and biotechnology. Applied Microbiology and Biotechnology 87, 479-489.
- Y. Anraku and Y. Satow (2009) Reflections on protein splicing: structures, functions and mechanisms. Proceedings of the Japan Academy, Series B, 85, 409-421.
- Y. Anraku, R. Mizutani and Y. Satow (2005) Protein splicing: its discovery and structural insight into novel chemical mechanisms. IUBMB Life 57, 563-574.
November 2010, David Goodsellhttp://doi.org/10.2210/rcsb_pdb/mom_2010_11