How water-soluble chlorophyll protein extracts chlorophyll from membranes
| Autor: | Philipp Girr, Harald Paulsen |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
0301 basic medicine Chlorophyll Circular dichroism Hot Temperature medicine.medical_treatment Biophysics macromolecular substances 01 natural sciences Biochemistry Lepidium Thylakoids 03 medical and health sciences chemistry.chemical_compound polycyclic compounds medicine Binding site Plant Proteins chemistry.chemical_classification Reactive oxygen species Protease food and beverages Membrane Proteins Water Cell Biology Amino acid 030104 developmental biology Membrane chemistry Solubility Thylakoid 010606 plant biology & botany |
| Zdroj: | Biochimica et biophysica acta. Biomembranes. 1863(1) |
| ISSN: | 1879-2642 |
| Popis: | Water-soluble chlorophyll proteins (WSCPs) found in Brassicaceae are non-photosynthetic proteins that bind only a small number of chlorophylls. Their biological function remains unclear, but recent data indicate that WSCPs are involved in stress response and pathogen defense as producers of reactive oxygen species and/or Chl-regulated protease inhibitors. For those functions, WSCP apoprotein supposedly binds Chl to become physiologically active or inactive, respectively. Thus, Chl-binding seems to be a pivotal step for the biological function of WSCP. WSCP can extract Chl from the thylakoid membrane but little is known about the mechanism of how Chl is sequestered from the membrane into the binding sites. Here, we investigate the interaction of WSCP with the thylakoid membrane in detail. The extraction of Chl from the thylakoid by WSCP apoprotein is a slow and inefficient reaction, because WSCP presumably does not directly extract Chl from other Chl-binding proteins embedded in the membrane. WSCP apoprotein interacts with model membranes that contain the thylakoid lipids MGDG, DGDG or PG, and can extract Chl from those. Furthermore, the WSCP-Chl complex, once formed, no longer interacts with membranes. We concluded that the surroundings of the WSCP pigment-binding site are involved in the WSCP-membrane interaction and identified a ring of hydrophobic amino acids with two conserved Trp residues around the Chl-binding site. Indeed, WSCP variants, in which one of the Trp residues was exchanged for Phe, still interact with the membrane but are no longer able to extract Chl. |
| Databáze: | OpenAIRE |
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