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Gated electron transfer reactions of truncated hemoglobin from Bacillus subtilis differently orientated on SAM-modified electrodes

Fapyane, Deby; Kartashov, Andrey; von Wachenfeldt, Claes LU and Ferapontova, Elena E. (2015) In Physical Chemistry Chemical Physics 17(23). p.15365-15374
Abstract
Electron transfer (ET) reactions of truncated hemoglobin from Bacillus subtilis (trHb-Bs) are suggested to be implicated in biological redox signalling and actuating processes that may be used in artificial environment-sensing bioelectronic devices. Here, kinetics of ET in trHb-Bs covalently attached via its surface amino acid residues either to COOH- or NH2-terminated (CH2)(2-16) alkanethiol SAM assembled on gold are shown to depend on the alkanethiol length and functionalization, not being limited by electron tunnelling through the SAMs but gated by ET preceding reactions due to conformational changes in the heme active site/at the interface. ET gating was sensitive to the properties of SAMs that trHb-Bs interacted with. The ET rate... (More)
Electron transfer (ET) reactions of truncated hemoglobin from Bacillus subtilis (trHb-Bs) are suggested to be implicated in biological redox signalling and actuating processes that may be used in artificial environment-sensing bioelectronic devices. Here, kinetics of ET in trHb-Bs covalently attached via its surface amino acid residues either to COOH- or NH2-terminated (CH2)(2-16) alkanethiol SAM assembled on gold are shown to depend on the alkanethiol length and functionalization, not being limited by electron tunnelling through the SAMs but gated by ET preceding reactions due to conformational changes in the heme active site/at the interface. ET gating was sensitive to the properties of SAMs that trHb-Bs interacted with. The ET rate constant k(s) for a 1e(-)/H+ reaction between the SAM-modified electrode and heme of trHb-Bs was 789 and 110 s(-1) after extrapolation to a zero length SAM, while the formal redox potential shifted 142 and 31 mV, for NH2- and COOH-terminated SAMs, respectively. Such domain-specific sensitivity and responsivity of redox reactions in trHb-Bs may be of immediate biological relevance and suggest the existence of bioelectronic regulative mechanisms of ET proceeding in vivo at the protein-protein charged interfaces that modulate the protein reactivity in biological redox signalling and actuating events. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Chemistry Chemical Physics
volume
17
issue
23
pages
15365 - 15374
publisher
Royal Society of Chemistry
external identifiers
  • wos:000355632900034
  • scopus:84930628229
ISSN
1463-9084
DOI
10.1039/c5cp00960j
language
English
LU publication?
yes
id
65fd4a21-1902-45bb-a9b7-11428baa1baa (old id 7606164)
date added to LUP
2015-07-22 08:42:58
date last changed
2017-01-15 03:45:02
@article{65fd4a21-1902-45bb-a9b7-11428baa1baa,
  abstract     = {Electron transfer (ET) reactions of truncated hemoglobin from Bacillus subtilis (trHb-Bs) are suggested to be implicated in biological redox signalling and actuating processes that may be used in artificial environment-sensing bioelectronic devices. Here, kinetics of ET in trHb-Bs covalently attached via its surface amino acid residues either to COOH- or NH2-terminated (CH2)(2-16) alkanethiol SAM assembled on gold are shown to depend on the alkanethiol length and functionalization, not being limited by electron tunnelling through the SAMs but gated by ET preceding reactions due to conformational changes in the heme active site/at the interface. ET gating was sensitive to the properties of SAMs that trHb-Bs interacted with. The ET rate constant k(s) for a 1e(-)/H+ reaction between the SAM-modified electrode and heme of trHb-Bs was 789 and 110 s(-1) after extrapolation to a zero length SAM, while the formal redox potential shifted 142 and 31 mV, for NH2- and COOH-terminated SAMs, respectively. Such domain-specific sensitivity and responsivity of redox reactions in trHb-Bs may be of immediate biological relevance and suggest the existence of bioelectronic regulative mechanisms of ET proceeding in vivo at the protein-protein charged interfaces that modulate the protein reactivity in biological redox signalling and actuating events.},
  author       = {Fapyane, Deby and Kartashov, Andrey and von Wachenfeldt, Claes and Ferapontova, Elena E.},
  issn         = {1463-9084},
  language     = {eng},
  number       = {23},
  pages        = {15365--15374},
  publisher    = {Royal Society of Chemistry},
  series       = {Physical Chemistry Chemical Physics},
  title        = {Gated electron transfer reactions of truncated hemoglobin from Bacillus subtilis differently orientated on SAM-modified electrodes},
  url          = {http://dx.doi.org/10.1039/c5cp00960j},
  volume       = {17},
  year         = {2015},
}