Titin: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
Titin, or Connectin, is the largest protein that has so far been discovered, undertaking the role of a structural and mechanical molecule, and it is commonly found in the [[Myofibril|myofibrils]] of skeletal [[Skeletal Muscle|muscle fibres]]. Within each [[Sarcomere|sarcomere]] they act as stable, long, elastic filaments that run from the Z disc to the M line region <ref>Nunes J.M., Hensen U, Ge L, Lipinsky M, Helenius J, Grubmüller H, Muller D.J. (2010) Angewandte Chemie International Edition, Volume 49 Issue 20, pp.3528-3531 [Peer Reviewed Journal]. [ONLINE] Available at http://onlinelibrary.wiley.com.libproxy.ncl.ac.uk/doi/10.1002/anie.200906388/full [Accessed 29 November 2012].</ref>. Its main function is to help stop muscles from over-stretching, or over-relaxing, by acting as a flexible and dynamic shock absorber <ref>Benichou I, Givli S (2011) Applied Physics Letters 98, 091904: The Hidden Ingenuity in Titin Structure [Peer Reviewed Journal] The American Institue of Physics. [ONLINE] Available at http://apl.aip.org.libproxy.ncl.ac.uk/resource/1/applab/v98/i9/p091904_s1 [Accessed 29 November 2012]</ref>. They are able to contract, tighten or even shrink in order to redirect the energy output whenever muscles stretch. | Titin, or Connectin, is the largest protein that has so far been discovered, undertaking the role of a structural and mechanical molecule, and it is commonly found in the [[Myofibril|myofibrils]] of skeletal [[Skeletal Muscle|muscle fibres]]. Within each [[Sarcomere|sarcomere]] they act as stable, long, elastic filaments that run from the Z disc to the M line region <ref>Nunes J.M., Hensen U, Ge L, Lipinsky M, Helenius J, Grubmüller H, Muller D.J. (2010) Angewandte Chemie International Edition, Volume 49 Issue 20, pp.3528-3531 [Peer Reviewed Journal].fckLR[ONLINE] Available at http://onlinelibrary.wiley.com.libproxy.ncl.ac.uk/doi/10.1002/anie.200906388/full [Accessed 29 November 2012].</ref>. Its main function is to help stop muscles from over-stretching, or over-relaxing, by acting as a flexible and dynamic shock absorber <ref>Benichou I, Givli S (2011) Applied Physics Letters 98, 091904: The Hidden Ingenuity in Titin Structure [Peer Reviewed Journal] The American Institue of Physics.fckLR[ONLINE] Available at http://apl.aip.org.libproxy.ncl.ac.uk/resource/1/applab/v98/i9/p091904_s1 [Accessed 29 November 2012]</ref>. They are able to contract, tighten or even shrink in order to redirect the energy output whenever muscles stretch. | ||
The titin protein is encoded by a single [[Gene|gene]], and in humans is known to have 363 [[Exon|exons]] that code for around 38,000 [[Amino acid|amino acids]] (3 | The titin protein is encoded by a single [[Gene|gene]], and in humans is known to have 363 [[Exon|exons]] that code for around 38,000 [[Amino acid|amino acids]] <ref>Granzier H.L., Labeit S (2004) Circulation Research 94: page 284-295: The Giant Protein Titin, American Heart Association.fckLR[ONLINE] Available at http://circres.ahajournals.org/content/94/3/284.full [Accessed 29 November 2012]</ref>. | ||
In the myofibril, titin helps place and align the thick [[Myosin|myosin]] filaments between the Z discs within the middle of the sarcomere. It contains long chains of specific domains that resemble [[Immunoglobulin|immunoglobulins]] – it is these domains that give the protein its characteristic spring-like elasticity. They can fold and unfold to maintain the structural arrangement of the thick filaments over the M line when the protein is undergoing stress or compression (3), thus acting as an entropic spring (4). | In the myofibril, titin helps place and align the thick [[Myosin|myosin]] filaments between the Z discs within the middle of the sarcomere. It contains long chains of specific domains that resemble [[Immunoglobulin|immunoglobulins]] – it is these domains that give the protein its characteristic spring-like elasticity. They can fold and unfold to maintain the structural arrangement of the thick filaments over the M line when the protein is undergoing stress or compression (3), thus acting as an entropic spring (4). | ||
Revision as of 23:03, 29 November 2012
Titin, or Connectin, is the largest protein that has so far been discovered, undertaking the role of a structural and mechanical molecule, and it is commonly found in the myofibrils of skeletal muscle fibres. Within each sarcomere they act as stable, long, elastic filaments that run from the Z disc to the M line region [1]. Its main function is to help stop muscles from over-stretching, or over-relaxing, by acting as a flexible and dynamic shock absorber [2]. They are able to contract, tighten or even shrink in order to redirect the energy output whenever muscles stretch.
The titin protein is encoded by a single gene, and in humans is known to have 363 exons that code for around 38,000 amino acids [3].
In the myofibril, titin helps place and align the thick myosin filaments between the Z discs within the middle of the sarcomere. It contains long chains of specific domains that resemble immunoglobulins – it is these domains that give the protein its characteristic spring-like elasticity. They can fold and unfold to maintain the structural arrangement of the thick filaments over the M line when the protein is undergoing stress or compression (3), thus acting as an entropic spring (4).
In recent experiments, it has been implied that titin shows traits of its function as a molecular ruler – where the sarcomere is longer, for example in the vertebrate C. Elegans, the titin filaments are also longer, showing a relationship between the length of titin and the length of the sarcomeres (4).
References
- ↑ Nunes J.M., Hensen U, Ge L, Lipinsky M, Helenius J, Grubmüller H, Muller D.J. (2010) Angewandte Chemie International Edition, Volume 49 Issue 20, pp.3528-3531 [Peer Reviewed Journal].fckLR[ONLINE] Available at http://onlinelibrary.wiley.com.libproxy.ncl.ac.uk/doi/10.1002/anie.200906388/full [Accessed 29 November 2012].
- ↑ Benichou I, Givli S (2011) Applied Physics Letters 98, 091904: The Hidden Ingenuity in Titin Structure [Peer Reviewed Journal] The American Institue of Physics.fckLR[ONLINE] Available at http://apl.aip.org.libproxy.ncl.ac.uk/resource/1/applab/v98/i9/p091904_s1 [Accessed 29 November 2012]
- ↑ Granzier H.L., Labeit S (2004) Circulation Research 94: page 284-295: The Giant Protein Titin, American Heart Association.fckLR[ONLINE] Available at http://circres.ahajournals.org/content/94/3/284.full [Accessed 29 November 2012]