PMID: 7017384Mar 1, 1981Paper

Light-induced changes in pH and buffer capacity in reaction center preparations of Rhodopseudomonas spheroides

Molekuliarnaia biologiia
M FabianA A Kononenko

Abstract

In experiments with reaction centers (RC) preparations of Rps. sphaeroides, strain 1760-1, pH of the suspension medium was found to change under continuous light excitation. The concentration of hydrogen ions starts to decrease fastly (t1/2 = 2--4 s) after the light is on, whereupon it increases slowly, to a steady-state level, within t1/2 = 5--7 min. During the fast phase 0.3 microM H+/1 microM of RC are absorbed and 7--8 microM H+/1 microM of RC are released under the slow phase. The fast phase is suppressed by ortho-phenantroline (10 mM)--an inhibitor of electron transfer from the primary (Fe-quinone complex) to the secondary (quinone) electron acceptors. Glutaraldehyde which is known to modify a protein structure of the RC inhibits the slow phase. The obtained data suggest that fast light-induced pH changes are due to a H+ uptake by the secondary quinoid anion-radical products; slow pH changes are ascribed to structural changes within the RC complex, which lead to a pK shift and/or changes in the amount of dissociating groups on the protein interfacial surface. The conclusion was supported by an observation of light-induced changes in buffer capacity of an RC suspension and by a light-induced increase in the amount of SH-gr...Continue Reading

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.