Journal article
Pathway Shifts and Thermal Softening in Temperature-Coupled Forced Unfolding of Spectrin Domains
Biophysical journal, v 85(5), pp 3286-3293
01 Nov 2003
PMID: 14581229
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Pathways of unfolding a protein depend in principle on the perturbation—whether it is temperature, denaturant, or even forced extension. Widely-shared, helical-bundle spectrin repeats are known to melt at temperatures as low as 40–45°C and are also known to unfold via multiple pathways as single molecules in atomic force microscopy. Given the varied roles of spectrin family proteins in cell deformability, we sought to determine the coupled effects of temperature on forced unfolding. Bimodal distributions of unfolding intervals are seen at all temperatures for the four-repeat
β
1–4
spectrin—an
α
-actinin homolog. The major unfolding length corresponds to unfolding of a single repeat, and a minor peak at twice the length corresponds to tandem repeats. Increasing temperature shows fewer tandem events but has no effect on unfolding intervals. As
T
approaches
T
m
, however, mean unfolding forces in atomic force microscopy also decrease; and circular dichroism studies demonstrate a nearly proportional decrease of helical content in solution. The results imply a thermal softening of a helical linker between repeats which otherwise propagates a helix-to-coil transition to adjacent repeats. In sum, structural changes with temperature correlate with both single-molecule unfolding forces and shifts in unfolding pathways.
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Details
- Title
- Pathway Shifts and Thermal Softening in Temperature-Coupled Forced Unfolding of Spectrin Domains
- Creators
- Richard Law - University of PennsylvaniaGeorge Liao - University of PennsylvaniaSandy Harper - The Wistar InstituteGuoliang Yang - Drexel UniversityDavid W. Speicher - University of PennsylvaniaDennis E. Discher - University of PennsylvaniaSteven G Harper - Surgery
- Publication Details
- Biophysical journal, v 85(5), pp 3286-3293
- Publisher
- Biophysical Society
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Surgery
- Web of Science ID
- WOS:000186190500048
- Scopus ID
- 2-s2.0-0242353807
- Other Identifier
- 991019167613304721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Biophysics