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Conformational Mechanics of Stimulus-Responsive Polypeptides

Publication ,  Journal Article
Valiaev, A; Clark, RL; Chilkoti, A; Zauscher, S
Published in: Proceedings of SPIE - The International Society for Optical Engineering
November 27, 2003

Stimulus-responsive polymers and polypeptides (SRPs) experience a significant entropic response when exposed to an environmental stimulus, such as a change in temperature. This phase transition directly affects polymer conformation and can potentially be harnessed for force generation in actuation devices on nano- and micro-scales. While interfacial applications of SRPs have been prototypically demonstrated, a systematic investigation of the phase transition behavior at the solid-liquid interface and on the single-molecule level is lacking. In this paper we present results from force-spectroscopy measurements probing the force-extension and conformational behavior of one SRP, elastin-like polypeptides (ELF), below and above their transition temperature. The results indicate that there is no significant difference in the force extension behavior at intermediate and large extensions, but the behavior is dramatically different at small extensions. Results also demonstrated that above the phase transition temperature large, unspecific adhesion forces often gave way to constant force steps upon extension, indicating a collapsed, potentially entangled, hydrophobic state of the ELP. The extension behavior below the phase transition temperature, however, closely followed that of a random polymer coil, without any significant unspecific adhesion forces. The excellent fit of a simple extended freely jointed chain model to the data at intermediate and large extensions suggests that the ELP is in a random conformational state without significant secondary structure. Forces associated with a phase transition therefore arise likely from entropic conformational changes associated with a hydrophobic collapse.

Duke Scholars

Published In

Proceedings of SPIE - The International Society for Optical Engineering

DOI

ISSN

0277-786X

Publication Date

November 27, 2003

Volume

5053

Start / End Page

31 / 40

Related Subject Headings

  • 5102 Atomic, molecular and optical physics
  • 4009 Electronics, sensors and digital hardware
  • 4006 Communications engineering
 

Citation

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Valiaev, A., Clark, R. L., Chilkoti, A., & Zauscher, S. (2003). Conformational Mechanics of Stimulus-Responsive Polypeptides. Proceedings of SPIE - The International Society for Optical Engineering, 5053, 31–40. https://doi.org/10.1117/12.484700
Valiaev, A., R. L. Clark, A. Chilkoti, and S. Zauscher. “Conformational Mechanics of Stimulus-Responsive Polypeptides.” Proceedings of SPIE - The International Society for Optical Engineering 5053 (November 27, 2003): 31–40. https://doi.org/10.1117/12.484700.
Valiaev A, Clark RL, Chilkoti A, Zauscher S. Conformational Mechanics of Stimulus-Responsive Polypeptides. Proceedings of SPIE - The International Society for Optical Engineering. 2003 Nov 27;5053:31–40.
Valiaev, A., et al. “Conformational Mechanics of Stimulus-Responsive Polypeptides.” Proceedings of SPIE - The International Society for Optical Engineering, vol. 5053, Nov. 2003, pp. 31–40. Scopus, doi:10.1117/12.484700.
Valiaev A, Clark RL, Chilkoti A, Zauscher S. Conformational Mechanics of Stimulus-Responsive Polypeptides. Proceedings of SPIE - The International Society for Optical Engineering. 2003 Nov 27;5053:31–40.

Published In

Proceedings of SPIE - The International Society for Optical Engineering

DOI

ISSN

0277-786X

Publication Date

November 27, 2003

Volume

5053

Start / End Page

31 / 40

Related Subject Headings

  • 5102 Atomic, molecular and optical physics
  • 4009 Electronics, sensors and digital hardware
  • 4006 Communications engineering