Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Channel Rhodopsins

Channel Rhodopsins

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,...

Anoxygenic Photosynthesis

Anoxygenic Photosynthesis

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 sulfur bacteria, heliobacteria, and...

Electron Transport Chain Components

Electron Transport Chain Components

The electron transport chain (ETC) is a crucial metabolic pathway that facilitates energy conversion in prokaryotic and eukaryotic cells. In eukaryotes, the ETC comprises four membrane-associated protein complexes in the inner mitochondrial membrane. In prokaryotes, the ETC in the plasma membrane can vary in composition, with fewer or different complexes depending on the organism and environmental conditions. These complexes transfer electrons from electron donors, such as NADH and FADH2, to...

The Photochemical Reaction Center

The Photochemical Reaction Center

Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...

Photoreceptors and Visual Pathways

Photoreceptors and Visual Pathways

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, whereas...

Anoxygenic Phototrophic Bacteria

Anoxygenic Phototrophic Bacteria

Anoxygenic phototrophic bacteria are a diverse group of microorganisms that perform photosynthesis without producing oxygen. They primarily include purple sulfur bacteria, purple nonsulfur bacteria, green sulfur bacteria, and green nonsulfur bacteria. These bacteria are classified into the Gammaproteobacteria, Alphaproteobacteria, Betaproteobacteria, Chlorobi, and Chloroflexi lineages, each with distinct physiological and ecological adaptations.Purple sulfur bacteria belong to the...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples.

Science (New York, N.Y.)·2022

Same author

Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth.

Science (New York, N.Y.)·2022

Same author

Sample collection from asteroid (162173) Ryugu by Hayabusa2: Implications for surface evolution.

Science (New York, N.Y.)·2020

Same author

An artificial impact on the asteroid (162173) Ryugu formed a crater in the gravity-dominated regime.

Science (New York, N.Y.)·2020

Same author

Direct observation of imploded core heating via fast electrons with super-penetration scheme.

Nature communications·2019

Same author

Images from the surface of asteroid Ryugu show rocks similar to carbonaceous chondrite meteorites.

Science (New York, N.Y.)·2019

Search research articles

Related Experiment Video

Updated: Jun 23, 2026

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

Bacteriorhodopsin is a powerful light-driven proton pump.

T Kouyama, A N Kouyama, A Ikegami

Biophysical Journal

|May 12, 2009

Summary

This summary is machine-generated.

Magnesium ions significantly boost bacteriorhodopsin

More Related Videos

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa

Published on: February 17, 2014

Electromechanical Assessment of Optogenetically Modulated Cardiomyocyte Activity

Electromechanical Assessment of Optogenetically Modulated Cardiomyocyte Activity

Published on: March 5, 2020

Related Experiment Videos

Last Updated: Jun 23, 2026

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa

Published on: February 17, 2014

Electromechanical Assessment of Optogenetically Modulated Cardiomyocyte Activity

Electromechanical Assessment of Optogenetically Modulated Cardiomyocyte Activity

Published on: March 5, 2020

Area of Science:

Biophysics
Molecular Biology

Background:

Bacteriorhodopsin is a light-driven proton pump found in Halobacterium halobium.
Its activity is crucial for cellular energy production and pH homeostasis.

Purpose of the Study:

To investigate the effect of magnesium ions on bacteriorhodopsin activity in cell envelopes.
To explore the role of internal pH in regulating proton pump function.

Main Methods:

Utilized Halobacterium halobium cell envelopes, devoid of cytoplasmic components.
Measured light-induced pH changes in the external medium under varying conditions.
Tested the influence of different divalent cations, including magnesium ions.

Main Results:

Physiological concentrations of magnesium ions dramatically enhanced light-induced pH changes.
Optimal conditions yielded a pH change of 3.5 units, significantly exceeding previous reports.
Divalent cations forming hydroxides below pH 10 were effective enhancers.

Conclusions:

Divalent cations, particularly magnesium, act as internal pH buffers, influencing bacteriorhodopsin activity.
Internal pH is a critical determinant of proton pump efficiency.
Bacteriorhodopsin maintains high proton-pump activity across a broad external pH range (4.5-9.4).