Mechanical strength of the titin Z1Z2-telethonin complex.
Using molecular dynamics simulations, we have explored the mechanical strength of the titin Z1Z2-telethonin complex, namely, its ability to bear strong forces such as those encountered during passive muscle stretch. Our results show that not only does this complex resist considerable mechanical force through beta strand crosslinking, suggesting that telethonin is an important component of the N-terminal titin anchor, but also that telethonin distributes these forces between its two joined titin Z2 domains to protect the proximal Z1 domains from bearing too much stress. Our simulations also reveal that without telethonin, apo-titin Z1Z2 exhibits significantly decreased resistance to mechanical stress, and that the N-terminal segment of telethonin (residues 1-89) does not exhibit a stable fold conformation when it is unbound from titin Z1Z2. Consequently, our study sheds light on a key but little studied architectural feature of biological cells-the existence of strong mechanical links that glue separate proteins together.
Center for Biophysics and Computational Biology and Beckman Institute, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801, USA.
Eric H
EH
Lee
Mu
M
Gao
Nikos
N
Pinotsis
Matthias
M
Wilmanns
Klaus
K
Schulten
D001665:Binding Sites; D003198:Computer Simulation; D064211:Connectin; D019281:Dimerization; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009124:Muscle Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012518:Sarcomeres / Q000737:chemistry*; D013314:Stress, Mechanical; D013329:Structure-Activity Relationship
D064211:Connectin; D009124:Muscle Proteins; C577292:TCAP protein, human; C577285:TTN protein, human; D011494:Protein Kinases