Molecule of the Month: Telomerase
Telomerase maintains the ends of our chromosomes.
Protecting the Ends
Add Six Bases, Repeat
Telomeres and Cancer
Exploring the Structure
Telomerase in Action
Telomerase is a highly dynamic complex that has been difficult to study. The structure of the catalytic core of telomerase was determined using cryo-electron tomography by using modified DNA nucleotides to lock the structure into a stable form that could be observed. The structure includes the template RNA (pink), the reverse transcriptase and several associated proteins (not shown here), and a short piece of the end of a DNA telomere (orange). This telomerase is from a protozoan, with telomeres that are slightly different than ours, with sequence TTGGGG. To explore this structure in more detail, click on the image for an interactive JSmol.
Topics for Further Discussion
- Retroviruses also use a reverse transcriptase to build DNA based on an RNA template. For example, you can see HIV reverse transcriptase in action in PDB entry 2hmi.
- G-quadruplexes have been observed with many variations in the arrangement of the four strands. Try searching at the RCSB PDB site for “quadruplex” to see them.
Related PDB-101 Resources
- Browse Nucleic Acids
- Browse Cancer
- Browse Nobel Prizes and PDB structures
- 6d6v: Jiang, J., Wang, Y., Susac, L., Chan, H., Basu, R., Zhou, Z.H., Feigon, J. (2018) Structure of telomerase with telomeric DNA. Cell 173: 1179-1190.e13
- Wu, R.A., Upton, H.E., Vogan, J.M., Collins, K. (2017) Telomerase mechanism of telomere synthesis. Annual Review of Biochemistry 86: 439-460.
- 143d: Wang, Y., Patel, D.J. (1993) Solution structure of the human telomeric repeat d[AG3(T2AG3)3] G-tetraplex. Structure 1: 263-282
November 2018, David Goodsellhttp://doi.org/10.2210/rcsb_pdb/mom_2018_11