Molecule of the Month: Titin
The giant protein titin organizes the structure of muscle and gives them elasticity
Exploring the Structure
Titin I65-I70 (PDB entry 3b43)
The individual domains in titin are connected by short, flexible linkers, giving the whole structure the look of beads on a string. PDB entry 3b43 includes a short segment with six Ig domains. The curvy shape of the structure gives some idea of the flexibility of the titin chain. To explore this structure in more detail, click on the image for an interactive JSmol.
Topics for Further Discussion
- You can look at the Protein Feature View for human titin to get an idea of the size of the protein, and the portions that are included in the PDB archive.
- Many flexible proteins are constructed from tandem repeats of modular protein domains, although not as many as is found in titin. Try, for instance, searching for structures in the PDB for immunoglobulins, fibronectin, and cadherin.
May 2015, David Goodselldoi:10.2210/rcsb_pdb/mom_2015_5