Molecule of the Month: Spliceosomes
Cryoelectron microscropy is revealing how spliceosomes cut-and-paste messenger RNA molecules.
The Splicing Reaction
The Role of RNA
Exploring the Structure
Spliceosome Intron Recognition
This close-up of the active site of the spliceosome shows how the ends of the intron "lariat" (yellow) are held by two small spliceosomal RNA molecules (colored magenta and red). One end of the intron is looped back and attached to the RNA 2' hydroxyl group (arrow). The two catalytic magnesium ions, which were involved in the previous splicing reactions, are shown nearby as magenta spheres. To explore this structure in more detail, click on the image for an interactive JSmol.
Topics for Further Discussion
- You can use resources like GenBank to look up the arrangement of exons and introns in genes, such as in the titin gene. For proteins in the PDB archive, the exon structure is shown by the Protein Feature View, such as the three exons in hemoglobin subunit alpha.
Related PDB-101 Resources
- Browse Nucleic Acids
- Browse Central Dogma
- Browse Cancer
- Browse Nobel Prizes and PDB structures
- 6n7p: Li, X., Liu, S., Zhang, L., Issaian, A., Hill, R.C., Espinosa, S., Shi, S., Cui, Y., Kappel, K., Das, R., Hansen, K.C., Zhou, Z.H., Zhao, R. (2019) A unified mechanism for intron and exon definition and back-splicing. Nature 573: 375-380
- Wilkinson, M.E., Charenton, C., Nagai, K. (2019) RNA splicing by the spliceosome. Ann. Rev. Biochem. 89, 1.1-1.30.
- Fica, S.M., Nagai, K. (2017) Cryo-electron microscopy snapshots of the spliceosome: structural insights into a dynamic ribonucleoprotein machine. Nat. Struct. Mol. Biol. 10, 791-799
- 3jb9: Yan, C., Hang, J., Wan, R., Huang, M., Wong, C., Shi, Y. (2015) Structure of a yeast spliceosome at 3.6-angstrom resolution. Science 349: 1182-1191
- 1ryf: Fiegen, D., Haeusler, L.C., Blumenstein, L., Herbrand, U., Dvorsky, R., Vetter, I.R., Ahmadian, M.R. (2004) Alternative Splicing of Rac1 Generates Rac1b, a Self-activating GTPase J.Biol.Chem. 279: 4743-4749
- 1mh1: Hirshberg, M., Stockley, R.W., Dodson, G., Webb, M.R. (1997) The crystal structure of human rac1, a member of the rho-family complexed with a GTP analogue. Nat.Struct.Mol.Biol. 4: 147-152
- Ward, A.J., Cooper, T.A. (2010) The pathobiology of splicing. J. Pathol. 220, 152-163
- Sharp, P.A. (1994) Nobel Lecture: Split genes and RNA splicing. Cell 77, 805-815
May 2020, David Goodsellhttp://doi.org/10.2210/rcsb_pdb/mom_2020_5