Document Detail


Temperature and Force Dependence of Nanoscale Electron Transport via the Cu Protein Azurin.
MedLine Citation:
PMID:  23136937     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Solid-state electron transport (ETp) via a monolayer of immobilized Azurin (Az) was examined by conducting probe atomic force microscopy (CP-AFM), both as function of temperature (248 - 373K) and applied tip force (6-12 nN). At low forces, ETp via holo-Az (with Cu+2) is temperature-independent, but thermally activated via the Cu-depleted form of Az, apo-Az. While this observation agrees with those of macroscopic-scale measurements, we find that for holo-Az the mechanism of ETp at high temperatures changes upon increasing the force applied by the tip to the proteins, viz. above 310K and forces >6 nN ETp becomes thermally activated. This is in contrast to apo-Az, where increasing applied force causes only small monotonic increases in currents due to decreased electrode separation. The distinct ETp temperature dependence of holo- and apo-Az is assigned to a difference in structural response to pressure between the two protein forms. An important implication of these CP-AFM results (of measurements over a significant temperature range) is that for reliable ETp measurements on flexible macromolecules, such as proteins, the pressure applied during the measurements should be controlled or at least monitored.
Authors:
Wenjie Li; Lior Sepunaru; Nadav Amdursky; Sidney R Cohen; Israel Pecht; Mordechai Sheves; David Cahen
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-11-8
Journal Detail:
Title:  ACS nano     Volume:  -     ISSN:  1936-086X     ISO Abbreviation:  ACS Nano     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101313589     Medline TA:  ACS Nano     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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