University of Illinois Urbana-Champaign

Computational Investigations of Cellular Functions: Three Cases on Membrane Morphogenesis, Organization and Assembly of a Multi-Protein Complex, and the Molecular Origin of Muscle Elasticity

Hsin, Ya-Chieh

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Description

Title
Computational Investigations of Cellular Functions: Three Cases on Membrane Morphogenesis, Organization and Assembly of a Multi-Protein Complex, and the Molecular Origin of Muscle Elasticity
Author(s)
Hsin, Ya-Chieh
Issue Date
2010
Doctoral Committee Chair(s)
  • Aksimentiev, Aleksei
  • Schulten, Klaus
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Biology, Cell
Language
eng
Abstract
Titin is a mechanical protein that protects muscle from overstretching by producing a restoring force when a muscle fiber is extended beyond its normal length. Force spectroscopy studies have shown that titin exhibits several regimes of elasticity. Disordered segments bring about a soft, entropic spring-type elasticity; secondary structures of titins immunoglobulin-like (Ig-) and fibronectin type III-like (FN-III) domains provide a stiff elasticity. We demonstrated that titin exhibits a third type of elasticity due to tertiary structure and involving domain-domain interaction and reorganization along the titin chain. Through simulations employing equilibrium molecular dynamics, steered molecular dynamics, and free-energy calculations, the mechanical properties of a six-Ig domain of titin (I65-I70), for which a crystallographic structure is available, were investigated. The results reveal a soft tertiary structure elasticity. A remarkably accurate statistical mechanical description for this elasticity is derived and applied. Simulations studied also the stiff, secondary structure elasticity of the I65-I70 chain due to the unraveling of its domains and revealed how force propagates along the chain during the secondary structure elasticity response.
Graduation Semester
2010
Type of Resource
text
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http://hdl.handle.net/2142/80632

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