The Photoactive Excited State of the B12-Based Photoreceptor CarH
We have used transient absorption spectroscopy in the UV-visible and X-ray regions to characterize the excited state of CarH, a protein photoreceptor that uses a form of B12, adenosylcobalamin (AdoCbl), to sense light. With visible excitation, a nanosecond-lifetime photoactive excited state is formed with unit quantum yield. The time-resolved X-ray absorption near edge structure difference spectrum of this state demonstrates that the excited state of AdoCbl in CarH undergoes only modest structural expansion around the central cobalt, a behavior similar to that observed for methylcobalamin rather than for AdoCbl free in solution. We propose a new mechanism for CarH photoreactivity involving formation of a triplet excited state. This allows the sensor to operate with high quantum efficiency and without formation of potentially dangerous side products. By stabilizing the excited electronic state, CarH controls reactivity of AdoCbl and enables slow reactions that yield nonreactive products and bypass bond homolysis and reactive radical species formation.
| Medienart: |
E-Artikel |
|---|
| Erscheinungsjahr: |
2020 |
|---|---|
| Erschienen: |
2020 |
| Enthalten in: |
Zur Gesamtaufnahme - volume:124 |
|---|---|
| Enthalten in: |
The journal of physical chemistry. B - 124(2020), 47 vom: 25. Nov., Seite 10732-10738 |
| Sprache: |
Englisch |
|---|
| Beteiligte Personen: |
Miller, Nicholas A [VerfasserIn] |
|---|
| Links: |
|---|
| Themen: |
3G0H8C9362 |
|---|
| Anmerkungen: |
Date Completed 14.05.2021 Date Revised 14.05.2021 published: Print-Electronic Citation Status MEDLINE |
|---|
| doi: |
10.1021/acs.jpcb.0c09428 |
|---|
| funding: |
|
|---|---|
| Förderinstitution / Projekttitel: |
|
| PPN (Katalog-ID): |
NLM317423940 |
|---|
| LEADER | 01000naa a22002652 4500 | ||
|---|---|---|---|
| 001 | NLM317423940 | ||
| 003 | DE-627 | ||
| 005 | 20231225163236.0 | ||
| 007 | cr uuu---uuuuu | ||
| 008 | 231225s2020 xx |||||o 00| ||eng c | ||
| 024 | 7 | |a 10.1021/acs.jpcb.0c09428 |2 doi | |
| 028 | 5 | 2 | |a pubmed24n1058.xml |
| 035 | |a (DE-627)NLM317423940 | ||
| 035 | |a (NLM)33174757 | ||
| 040 | |a DE-627 |b ger |c DE-627 |e rakwb | ||
| 041 | |a eng | ||
| 100 | 1 | |a Miller, Nicholas A |e verfasserin |4 aut | |
| 245 | 1 | 4 | |a The Photoactive Excited State of the B12-Based Photoreceptor CarH |
| 264 | 1 | |c 2020 | |
| 336 | |a Text |b txt |2 rdacontent | ||
| 337 | |a ƒaComputermedien |b c |2 rdamedia | ||
| 338 | |a ƒa Online-Ressource |b cr |2 rdacarrier | ||
| 500 | |a Date Completed 14.05.2021 | ||
| 500 | |a Date Revised 14.05.2021 | ||
| 500 | |a published: Print-Electronic | ||
| 500 | |a Citation Status MEDLINE | ||
| 520 | |a We have used transient absorption spectroscopy in the UV-visible and X-ray regions to characterize the excited state of CarH, a protein photoreceptor that uses a form of B12, adenosylcobalamin (AdoCbl), to sense light. With visible excitation, a nanosecond-lifetime photoactive excited state is formed with unit quantum yield. The time-resolved X-ray absorption near edge structure difference spectrum of this state demonstrates that the excited state of AdoCbl in CarH undergoes only modest structural expansion around the central cobalt, a behavior similar to that observed for methylcobalamin rather than for AdoCbl free in solution. We propose a new mechanism for CarH photoreactivity involving formation of a triplet excited state. This allows the sensor to operate with high quantum efficiency and without formation of potentially dangerous side products. By stabilizing the excited electronic state, CarH controls reactivity of AdoCbl and enables slow reactions that yield nonreactive products and bypass bond homolysis and reactive radical species formation | ||
| 650 | 4 | |a Journal Article | |
| 650 | 4 | |a Research Support, Non-U.S. Gov't | |
| 650 | 4 | |a Research Support, U.S. Gov't, Non-P.H.S. | |
| 650 | 7 | |a Cobalt |2 NLM | |
| 650 | 7 | |a 3G0H8C9362 |2 NLM | |
| 700 | 1 | |a Kaneshiro, April K |e verfasserin |4 aut | |
| 700 | 1 | |a Konar, Arkaprabha |e verfasserin |4 aut | |
| 700 | 1 | |a Alonso-Mori, Roberto |e verfasserin |4 aut | |
| 700 | 1 | |a Britz, Alexander |e verfasserin |4 aut | |
| 700 | 1 | |a Deb, Aniruddha |e verfasserin |4 aut | |
| 700 | 1 | |a Glownia, James M |e verfasserin |4 aut | |
| 700 | 1 | |a Koralek, Jake D |e verfasserin |4 aut | |
| 700 | 1 | |a Mallik, Leena |e verfasserin |4 aut | |
| 700 | 1 | |a Meadows, Joseph H |e verfasserin |4 aut | |
| 700 | 1 | |a Michocki, Lindsay B |e verfasserin |4 aut | |
| 700 | 1 | |a van Driel, Tim B |e verfasserin |4 aut | |
| 700 | 1 | |a Koutmos, Markos |e verfasserin |4 aut | |
| 700 | 1 | |a Padmanabhan, S |e verfasserin |4 aut | |
| 700 | 1 | |a Elías-Arnanz, Montserrat |e verfasserin |4 aut | |
| 700 | 1 | |a Kubarych, Kevin J |e verfasserin |4 aut | |
| 700 | 1 | |a Marsh, E Neil G |e verfasserin |4 aut | |
| 700 | 1 | |a Penner-Hahn, James E |e verfasserin |4 aut | |
| 700 | 1 | |a Sension, Roseanne J |e verfasserin |4 aut | |
| 773 | 0 | 8 | |i Enthalten in |t The journal of physical chemistry. B |d 1997 |g 124(2020), 47 vom: 25. Nov., Seite 10732-10738 |w (DE-627)NLM114379831 |x 1520-5207 |7 nnns |
| 773 | 1 | 8 | |g volume:124 |g year:2020 |g number:47 |g day:25 |g month:11 |g pages:10732-10738 |
| 856 | 4 | 0 | |u http://dx.doi.org/10.1021/acs.jpcb.0c09428 |3 Volltext |
| 912 | |a GBV_USEFLAG_A | ||
| 912 | |a GBV_NLM | ||
| 951 | |a AR | ||
| 952 | |d 124 |j 2020 |e 47 |b 25 |c 11 |h 10732-10738 | ||