Proximity channeling during cyanobacterial phycoerythrobilin synthesis
| Autor: | Jana Hartmann, Nicole Frankenberg-Dinkel, Volker Hartmann, Marco Aras, Marc M. Nowaczyk |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Stereochemistry Substrate channeling Phycoerythrobilin Cyanobacteria Biochemistry 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Bacterial Proteins Phycobilins Oxidoreductase Bilin Molecular Biology Ferredoxin chemistry.chemical_classification Biliverdin Biliverdine Phycoerythrin Cell Biology Enzymes Immobilized Tetrapyrrole Metabolic pathway 030104 developmental biology chemistry 030220 oncology & carcinogenesis Oxidoreductases |
| Zdroj: | The FEBS Journal. 287:284-294 |
| ISSN: | 1742-4658 1742-464X |
| DOI: | 10.1111/febs.15003 |
| Popis: | Substrate channeling is a widespread mechanism in metabolic pathways to avoid decomposition of unstable intermediates, competing reactions, and to accelerate catalytic turnover. During the biosynthesis of light-harvesting phycobilins in cyanobacteria, two members of the ferredoxin-dependent bilin reductases are involved in the reduction of the open-chain tetrapyrrole biliverdin IXα to the pink pigment phycoerythrobilin. The first reaction is catalyzed by 15,16-dihydrobiliverdin:ferredoxin oxidoreductase and produces the unstable intermediate 15,16-dihydrobiliverdin (DHBV). This intermediate is subsequently converted by phycoerythrobilin:ferredoxin oxidoreductase to the final product phycoerythrobilin. Although substrate channeling has been postulated already a decade ago, detailed experimental evidence was missing. Using a new on-column assay employing immobilized enzyme in combination with UV-Vis and fluorescence spectroscopy revealed that both enzymes transiently interact and that transfer of the intermediate is facilitated by a significantly higher binding affinity of DHBV toward phycoerythrobilin:ferredoxin oxidoreductase. Concluding from the presented data, the intermediate DHBV is transferred via proximity channeling. |
| Databáze: | OpenAIRE |
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