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Force-induced prolyl cis-trans isomerization in elastin-like polypeptides.

Publication ,  Journal Article
Valiaev, A; Lim, DW; Oas, TG; Chilkoti, A; Zauscher, S
Published in: J Am Chem Soc
May 23, 2007

Elastin-like polypeptides (ELPs) are stimulus-responsive polymers that contain repeats of five amino acids, Val-Pro-Gly-Xaa-Gly (VPGXG), where Xaa is a guest residue that can be any amino acid with the exception of proline. While studying the conformational mechanics of ELPs over a range of solvent conditions by single-molecule force spectroscopy, we noticed that some force-extension curves showed temperature-independent, extensional transitions that could not be fitted with a freely jointed chain or worm-like chain model. Here we show that the observed molecular elongation results from the force-induced peptidyl-prolyl cis-trans isomerization in prolines, which are repeated every fifth residue in the main chain of ELPs. Control experiments with poly(L-proline) demonstrate the similarity of the conformational transition between poly(L-proline) and ELPs. In contrast, the force-extension behavior of poly(L-lysine) showed no deviation in the relevant force range. Force-extension curves in hysteresis experiments showed an elongational difference between extension and relaxation pathways that suggests that the cis conformational state of the prolines could be exhausted on the time scale of the experiment. We present further computational evidence for this mechanism by Monte Carlo simulation of the force-extension behavior using an elastically coupled, two-state model. We believe ours is the first demonstration of force-induced prolyl cis-trans isomerization in proline-containing polypeptides. Our results suggest that single-molecule force spectroscopy could provide an alternate means to assay this important conformational transition in polypeptides.

Duke Scholars

Published In

J Am Chem Soc

DOI

ISSN

0002-7863

Publication Date

May 23, 2007

Volume

129

Issue

20

Start / End Page

6491 / 6497

Location

United States

Related Subject Headings

  • Stress, Mechanical
  • Spectrum Analysis
  • Proline
  • Oligopeptides
  • Molecular Conformation
  • Models, Molecular
  • Kinetics
  • Isomerism
  • Isoleucine
  • General Chemistry
 

Citation

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Valiaev, A., Lim, D. W., Oas, T. G., Chilkoti, A., & Zauscher, S. (2007). Force-induced prolyl cis-trans isomerization in elastin-like polypeptides. J Am Chem Soc, 129(20), 6491–6497. https://doi.org/10.1021/ja070147r
Valiaev, Alexei, Dong Woo Lim, Terrence G. Oas, Ashutosh Chilkoti, and Stefan Zauscher. “Force-induced prolyl cis-trans isomerization in elastin-like polypeptides.J Am Chem Soc 129, no. 20 (May 23, 2007): 6491–97. https://doi.org/10.1021/ja070147r.
Valiaev A, Lim DW, Oas TG, Chilkoti A, Zauscher S. Force-induced prolyl cis-trans isomerization in elastin-like polypeptides. J Am Chem Soc. 2007 May 23;129(20):6491–7.
Valiaev, Alexei, et al. “Force-induced prolyl cis-trans isomerization in elastin-like polypeptides.J Am Chem Soc, vol. 129, no. 20, May 2007, pp. 6491–97. Pubmed, doi:10.1021/ja070147r.
Valiaev A, Lim DW, Oas TG, Chilkoti A, Zauscher S. Force-induced prolyl cis-trans isomerization in elastin-like polypeptides. J Am Chem Soc. 2007 May 23;129(20):6491–6497.
Journal cover image

Published In

J Am Chem Soc

DOI

ISSN

0002-7863

Publication Date

May 23, 2007

Volume

129

Issue

20

Start / End Page

6491 / 6497

Location

United States

Related Subject Headings

  • Stress, Mechanical
  • Spectrum Analysis
  • Proline
  • Oligopeptides
  • Molecular Conformation
  • Models, Molecular
  • Kinetics
  • Isomerism
  • Isoleucine
  • General Chemistry