NADPH-dependent sulfite reductase flavoprotein adopts an extended conformation unique to this diflavin reductase
| Autor: | Isabel Askenasy, M. Elizabeth Stroupe, Christopher B. Stanley, Angela M. Tavolieri, Lauren McGarry, Daniel T. Murray, Joseph M. Pennington |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0303 health sciences
Oxidase test Flavoproteins biology Chemistry Stereochemistry Protein subunit 030302 biochemistry & molecular biology Flavoprotein Cytochrome P450 reductase Reductase Crystallography X-Ray Sulfite reductase 03 medical and health sciences Electron transfer Structural Biology Intramolecular force biology.protein Sulfite Reductase (NADPH) NADPH-Ferrihemoprotein Reductase 030304 developmental biology |
| Zdroj: | Journal of Structural Biology. 205:170-179 |
| ISSN: | 1047-8477 |
| Popis: | This is the first X-ray crystal structure of the monomeric form of sulfite reductase (SiR) flavoprotein (SiRFP-60) that shows the relationship between its major domains in an extended position not seen before in any homologous diflavin reductases. Small angle neutron scattering confirms this novel domain orientation also occurs in solution. Activity measurements of SiR and SiRFP variants allow us to propose a novel mechanism for electron transfer from the SiRFP reductase subunit to its oxidase metalloenzyme partner that, together, make up the SiR holoenzyme. Specifically, we propose that SiR performs its 6-electron reduction via intramolecular or intermolecular electron transfer. Our model explains both the significance of the stoichiometric mismatch between reductase and oxidase subunits in the holoenzyme and how SiR can handle such a large volume electron reduction reaction that is at the heart of the sulfur bio-geo cycle. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect