Related Experiment Video
Updated: Jul 26, 2025
08:09
Electrophysiological Methods for Measuring Photopigment Levels in Drosophila Photoreceptors
Published on: June 2, 2022
2.3K
Exploring isotropic tendency for the blue membrane containing wild-type bacteriorhodopsin.
1Department of Biophysics, Faculty of Science, Cairo University, 11757 Giza, Egypt.
Biophysical Chemistry
|June 21, 2023
Summary
Bacteriorhodopsin
Area of Science:
- Biophysics
- Materials Science
Background:
- Bacteriorhodopsin in purple membranes has potential in bioelectronics and biophotonic nanodevices.
- Acidification induces structural changes in bacteriorhodopsin, affecting its color and properties.
Purpose of the Study:
- To investigate the acidic pH dependence of bacteriorhodopsin's anisotropic properties.
- To correlate structural changes with electric impedance measurements.
Main Methods:
- Measured electric impedance of parallel-, perpendicular-, and randomly-oriented purple membranes across an acidic pH range.
- Analyzed electric anisotropy in relation to color transitions.
Main Results:
- Electric anisotropy correlates with color transitions at low pH, with consistent pKa values.
- Bacteriorhodopsin becomes isotropic around pH 2.55 in its blue form, retaining anisotropy in its purple form.
Conclusions:
- The pH-dependent isotropic tendency of bacteriorhodopsin in its blue form suggests potential for novel technical applications.
- Understanding these acid-induced changes is crucial for developing advanced nanodevices.
More Related Videos
Related Concept Videos
01:11Channel Rhodopsins
2.6K
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
2.6K
01:35Asymmetric Lipid Bilayer
7.3K
Biological membranes show uneven distribution of different types of lipids in the inner and outer layers, resulting in transverse asymmetric membranes. The treatment of the erythrocyte membrane with the enzyme phospholipase confirmed the asymmetric nature of the lipid bilayer. The enzyme hydrolyzes lipids into fatty acids and hydrophilic groups. The phospholipase acts only on the outer layer of the membrane, while the inner layer remains intact. The phospholipase treatment resulted in 80%...
7.3K
01:30Anoxygenic Photosynthesis
54
Anoxygenic photosynthesis is a phototrophic process that captures light energy to drive carbon fixation without producing molecular oxygen. Unlike oxygenic photosynthesis, which utilizes water as an electron donor and releases oxygen, anoxygenic phototrophs use alternative electron donors such as hydrogen sulfide (H₂S), elemental sulfur (S⁰), or thiosulfate (S₂O₃²⁻). This process is carried out by diverse groups of bacteria, including purple bacteria, green...
54
01:22Photoreceptors and Visual Pathways
6.1K
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category,...
6.1K
01:09Multi-pass Transmembrane Proteins and β-barrels
5.4K
In multi-pass transmembrane proteins, the polypeptide chain crosses the membrane more than once. The transmembrane polypeptide chain either forms an α-helix or β-strand structure. α-Helix containing multi-pass transmembrane proteins are ubiquitous, whereas β-strand containing ones are mainly found in gram-negative bacteria, mitochondria, and chloroplasts.
α-Helix containing multi-pass transmembrane proteins
Multi-pass transmembrane proteins such as...
α-Helix containing multi-pass transmembrane proteins
Multi-pass transmembrane proteins such as...
5.4K
01:21G-Protein Gated Ion Channels
4.6K
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory...
Sensory...
4.6K