Conformational mechanics of stimulus-responsive polypeptides

Alexei Valiaev; Robert L. Clark; Ashutosh Chilkoti; Stefan Zauscher

doi:10.1117/12.484700

13 August 2003 Conformational mechanics of stimulus-responsive polypeptides

Alexei Valiaev, Robert L. Clark, Ashutosh Chilkoti, Stefan Zauscher

Proceedings Volume 5053, Smart Structures and Materials 2003: Active Materials: Behavior and Mechanics; (2003) https://doi.org/10.1117/12.484700
Event: Smart Structures and Materials, 2003, San Diego, California, United States

Abstract

Stimulus-responsive polymers and polypeptides (SRPs) experience a significant entropic response when exposed to an environemental 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 (ELP), below and above their transition temperature. The results indicate that there is no signficant 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 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 extension 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.

Citation Download Citation

Alexei Valiaev, Robert L. Clark, Ashutosh Chilkoti, and Stefan Zauscher "Conformational mechanics of stimulus-responsive polypeptides", Proc. SPIE 5053, Smart Structures and Materials 2003: Active Materials: Behavior and Mechanics, (13 August 2003); https://doi.org/10.1117/12.484700

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available