Two Tryptophans Are Better Than One in Accelerating Electron Flow through a Protein
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388955%3A_____%2F19%3A00500238" target="_blank" >RIV/61388955:_____/19:00500238 - isvavai.cz</a>
Alternative codes found
RIV/60461373:22340/19:43918694
Result on the web
<a href="http://hdl.handle.net/11104/0292342" target="_blank" >http://hdl.handle.net/11104/0292342</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/acscentsci.8b00882" target="_blank" >10.1021/acscentsci.8b00882</a>
Alternative languages
Result language
angličtina
Original language name
Two Tryptophans Are Better Than One in Accelerating Electron Flow through a Protein
Original language description
We have constructed and structurally characterized a Pseudomonas aeruginosa azurin mutant Re126WWCu(I), where two adjacent tryptophan residues (W124 and W122, indole separation 3.6-4.1 angstrom) are inserted between the CuI center and a Re photosensitizer coordinated to the imidazole of H126 (Re-I(H126)-(CO)(3)(4,7-dimethyl-1,10-phenanthroline)(+)). Cu-I oxidation by the photoexcited Re label (*Re) 22.9 angstrom away proceeds with a similar to 70 ns time constant, similar to that of a single-tryptophan mutant (similar to 40 ns) with a 19.4 angstrom Re-Cu distance. Time-resolved spectroscopy (luminescence, visible and IR absorption) revealed two rapid reversible electron transfer steps, W124 -> *Re (400-475 ps, K-1 congruent to 3.5-4) and W122 -> W124(center dot+) (7-9 ns, K-2 congruent to 0.55-0.75), followed by a rate-determining (70-90 ns) Cu-I oxidation by W122(+) ca. 11 angstrom away. The photocycle is completed by 120 mu s recombination. No photochemical Cu-I oxidation was observed in Re126FWCu(I), whereas in Re126WFCu(I), the photocycle is restricted to the ReH126W124 unit and Cu-I remains isolated. QM/MM/MD simulations of Re126WWCu(I) indicate that indole solvation changes through the hopping process and W124 -> *Re electron transfer is accompanied by water fluctuations that tighten W124 solvation. Our finding that multistep tunneling (hopping) confers a similar to 9000-fold advantage over single-step tunneling in the double-tryptophan protein supports the proposal that hole-hopping through tryptophan/tyrosine chains protects enzymes from oxidative damage.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10403 - Physical chemistry
Result continuities
Project
<a href="/en/project/GA17-01137S" target="_blank" >GA17-01137S: Electron Transfer in (Bio)Molecular Systems: Time-Resolved Vibrational Spectroscopy and Theory</a><br>
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2019
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
ACS Central Science
ISSN
2374-7943
e-ISSN
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Volume of the periodical
5
Issue of the periodical within the volume
1
Country of publishing house
US - UNITED STATES
Number of pages
9
Pages from-to
192-200
UT code for WoS article
000456525100021
EID of the result in the Scopus database
2-s2.0-85059803970