Ultrafast excited-state deactivation of flavins bound to dodecin
- Dodecins, a group of flavin-binding proteins with a dodecameric quaternary structure, are able to incorporate two flavins within each of their six identical binding pockets building an aromatic tetrade with two tryptophan residues. Dodecin from the archaeal Halobacterium salinarum is a riboflavin storage device. We demonstrate that unwanted side reactions induced by reactive riboflavin species and degradation of riboflavin are avoided by ultrafast depopulation of the reactive excited state of riboflavin. Intriguingly, in this process, the staggered riboflavin dimers do not interact in ground and photoexcited states. Rather, within the tetrade assembly, each riboflavin is kept under the control of the respective adjacent tryptophan, which suggests that the stacked arrangement is a matter of optimizing the flavin load. We further identify an electron transfer in combination with a proton transfer as a central element of the effective excited state depopulation mechanism. Structural and functional comparisons of the archaeal dodecin with bacterial homologs reveal diverging evolution. Bacterial dodecins bind the flavin FMN instead of riboflavin and exhibit a clearly different binding pocket design with inverse incorporations of flavin dimers. The different adoption of flavin changes photochemical properties, making bacterial dodecin a comparably less efficient quencher of flavins. This supports a functional role different for bacterial and archaeal dodecins.
Author: | Heike StaudtGND, Dieter OesterheltGND, Martin GriningerORCiDGND, Josef WachtveitlORCiDGND |
---|---|
URN: | urn:nbn:de:hebis:30:3-766650 |
DOI: | https://doi.org/10.1074/jbc.M111.331652 |
ISSN: | 0021-9258 |
Pubmed Id: | https://pubmed.ncbi.nlm.nih.gov/22451648 |
Parent Title (English): | Journal of biological chemistry |
Publisher: | American Society for Biochemistry and Molecular Biology Publications |
Place of publication: | Bethesda, Md |
Document Type: | Article |
Language: | English |
Date of Publication (online): | 2021/01/04 |
Year of first Publication: | 2012 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2023/11/27 |
Tag: | Electron Transfer; Flavin; Flavin-binding Protein; Flavoproteins; Protein Dynamics; Proton Transfer; Spectroscopy; Ultrafast Spectroscopy |
Volume: | 287 |
Issue: | 21 |
Page Number: | 8 |
First Page: | 17637 |
Last Page: | 17644 |
HeBIS-PPN: | 51650844X |
Institutes: | Biochemie, Chemie und Pharmazie / Biochemie und Chemie |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie | |
Sammlungen: | Universitätspublikationen |
Licence (German): | Creative Commons - CC BY - Namensnennung 4.0 International |