---
_id: '3721'
abstract:
- lang: eng
text: Recent advances in atomic force microscopy allowed globular and membrane proteins
to be mechanically unfolded on a single-molecule level. Presented is an extension
to the existing force spectroscopy experiments. While unfolding single bacteriorhodopsins
from native purple membranes, small oscillation amplitudes (6–9nm) were supplied
to the vertical displacement of the cantilever at a frequency of 3kHz. The phase
and amplitude response of the cantilever-protein system was converted to reveal
the elastic (conservative) and viscous (dissipative) contributions to the unfolding
process. The elastic response (stiffness) of the extended parts of the protein
were in the range of a few tens pN/nm and could be well described by the derivative
of the wormlike chain model. Discrete events in the viscous response coincided
with the unfolding of single secondary structure elements and were in the range
of 1μNs/m. In addition, these force modulation spectroscopy experiments revealed
novel mechanical unfolding intermediates of bacteriorhodopsin. We found that kinks
result in a loss of unfolding cooperativity in transmembrane helices. Reconstructing
force-distance spectra by the integration of amplitude-distance spectra verified
their position, offering a novel approach to detect intermediates during the forced
unfolding of single proteins.
author:
- first_name: Harald L
full_name: Harald Janovjak
id: 33BA6C30-F248-11E8-B48F-1D18A9856A87
last_name: Janovjak
orcid: 0000-0002-8023-9315
- first_name: Daniel
full_name: Mueller, Daniel J
last_name: Mueller
- first_name: Andrew
full_name: Humphris, Andrew D
last_name: Humphris
citation:
ama: Janovjak HL, Mueller D, Humphris A. Molecular force modulation spectroscopy
revealing the dynamic response of single bacteriorhodopsins. Biophysical Journal.
2005;88(2):1423-1431. doi:10.1529/biophysj.104.052746
apa: Janovjak, H. L., Mueller, D., & Humphris, A. (2005). Molecular force modulation
spectroscopy revealing the dynamic response of single bacteriorhodopsins. Biophysical
Journal. Biophysical Society. https://doi.org/10.1529/biophysj.104.052746
chicago: Janovjak, Harald L, Daniel Mueller, and Andrew Humphris. “Molecular Force
Modulation Spectroscopy Revealing the Dynamic Response of Single Bacteriorhodopsins.”
Biophysical Journal. Biophysical Society, 2005. https://doi.org/10.1529/biophysj.104.052746.
ieee: H. L. Janovjak, D. Mueller, and A. Humphris, “Molecular force modulation spectroscopy
revealing the dynamic response of single bacteriorhodopsins,” Biophysical Journal,
vol. 88, no. 2. Biophysical Society, pp. 1423–1431, 2005.
ista: Janovjak HL, Mueller D, Humphris A. 2005. Molecular force modulation spectroscopy
revealing the dynamic response of single bacteriorhodopsins. Biophysical Journal.
88(2), 1423–1431.
mla: Janovjak, Harald L., et al. “Molecular Force Modulation Spectroscopy Revealing
the Dynamic Response of Single Bacteriorhodopsins.” Biophysical Journal,
vol. 88, no. 2, Biophysical Society, 2005, pp. 1423–31, doi:10.1529/biophysj.104.052746.
short: H.L. Janovjak, D. Mueller, A. Humphris, Biophysical Journal 88 (2005) 1423–1431.
date_created: 2018-12-11T12:04:48Z
date_published: 2005-02-01T00:00:00Z
date_updated: 2021-01-12T07:51:43Z
day: '01'
doi: 10.1529/biophysj.104.052746
extern: 1
intvolume: ' 88'
issue: '2'
main_file_link:
- open_access: '1'
url: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1305144/
month: '02'
oa: 1
page: 1423 - 1431
publication: Biophysical Journal
publication_status: published
publisher: Biophysical Society
publist_id: '2509'
quality_controlled: 0
status: public
title: Molecular force modulation spectroscopy revealing the dynamic response of single
bacteriorhodopsins
type: journal_article
volume: 88
year: '2005'
...