Two Tryptophans Are Better Than One in Accelerating Electron Flow through a Protein

Kód výsledku v 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>

Nalezeny alternativní kódy

RIV/60461373:22340/19:43918694

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

Two Tryptophans Are Better Than One in Accelerating Electron Flow through a Protein

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

Two Tryptophans Are Better Than One in Accelerating Electron Flow through a Protein

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

<a href="/cs/project/GA17-01137S" target="_blank" >GA17-01137S: Přenos elektronu v (bio)molekulárních systémech: časově rozlišená vibrační spektroskopie a teorie</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

ACS Central Science

ISSN

2374-7943

e-ISSN

—

Svazek periodika

5

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

9

Strana od-do

192-200

Kód UT WoS článku

000456525100021

EID výsledku v databázi Scopus

2-s2.0-85059803970