07/13/2023
By Suzanne Young

The Kennedy College of Sciences, Department of Chemistry, invites you to attend a Master’s thesis defense by Smita Chatterjee entitled "Titin Ig Domains Demonstrate Variable Stability Within the Proximal Ig Segment".

Degree: Master's
Date: Wednesday, July 26, 2023
Time: noon
Location: Olney 518

Committee Chair: Prof. Matthew Gage, Department of Chemistry, University of Massachusetts Lowell

Committee Members:

  • Prof. Juan Artes-Vivancos, Department of Chemistry, University of Massachusetts Lowell
  • Prof. Michael B. Ross, Department of Chemistry, University of Massachusetts Lowell

Abstract:
Titin is a giant filamentous protein contributing to the passive elasticity of muscle and is composed of approximately 300vserially linked immunoglobulin-like (Ig) domains. The tandem domains of titin’s proximal Ig segment have been shown to separate at relatively low forces and thus contribute to the protein’s elasticity. While titin’s elastic behavior is attributed to extension of the proximal Ig and PEVK regions beyond slack length, the potential unfolding of individual Ig domains has been posited to contribute to even greater extensibility. Computational modeling and mechanical stability testing have demonstrated Ig domain unfolding under physiologically relevant force, with neighboring domains exhibiting variable degrees of stability. Thermal and chemical stability experiments were conducted on domains I65-I70 of the proximal tandem Ig segment to evaluate the stability of adjacent domains. Testing revealed variable free energies of unfolding, with I67 demonstrating the lowest thermal and chemical stability and I70 demonstrating the highest. This work confirms theoretical modeling of differential Ig domain stability and provides greater insight into the role of the proximal Ig segment in titin’s elasticity. The observed variations in stability may allow for greater control over sequential unfolding events, with domains extending in an alternating fashion to prevent unwanted overextension.

All interested students and faculty members are invited to attend.