Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
9.4
4.8
Journals
Biomolecules
Special Issues
New Insights into the Membranes of Anoxygenic Phototrophic Bacteria
share announcement

New Insights into the Membranes of Anoxygenic Phototrophic Bacteria

A special issue of Biomolecules (ISSN 2218-273X). This special issue belongs to the section "Molecular Structure and Dynamics".

Deadline for manuscript submissions: 30 April 2025 | Viewed by 2029

Special Issue Editor

Prof. Dr. Robert A. Niederman

E-Mail Website
Guest Editor
Department of Molecular Biology and Biochemistry and Rutgers Energy Institute, Rutgers University, Piscataway, NJ 08854, USA
Interests: membrane biochemistry; biophysics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Central to the photosynthetic membranes of anoxygenic phototrophic bacteria are the reaction center-photosystems (RC-PS) which catalyze the harvesting and transduction of solar energy. The numerous recent high-resolution structures, arising largely from advances in cyro-electron microscopy, have revealed a considerable diversity in the  molecular architecture of both the heterodimeric Type II (pheophytin-quinone-type, quinone-reducing) RC-PSs (RC- light-harvesting 1 complexes) of purple bacteria and homodimeric Type I (Fe-S-type, ferredoxin-reducing) RC-PSs of heliobacteria, green sulfur bacteria, and chloroacetobacteria. Importantly, these latter structures have provided a considerable body of crucial evidence supporting roles for homodimeric RC-PSs in the evolution of extant heterodimeric PSI and PSII complexes of oxygenic phototrophs.

This Special Issue of Biomolecules will focus on the recent advances in understanding the structures, functions, and assembly of bacterial photosynthetic membranes. Special emphasis will be placed on how these studies are providing further insights into the evolution of oxygenic phototrophs, largely responsible for the rise in atmospheric O2 levels that facilitated the subsequent evolution of life on Earth. Additionally, we will address the manner in which these new structures form the basis for the construction of improved biohybrid and biomimetic photoelectrochemical devices, as well as molecular dynamics simulations serving to test hypothetical mechanisms which these structures have inspired.

Prof. Dr. Robert A. Niederman
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Biomolecules is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • anoxygenic phototrophs
  • light harvesting
  • membrane dynamics
  • molecular evolution
  • reaction centers

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (2 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

22 pages, 4619 KiB  
Article
Contribution of Protonation to the Dielectric Relaxation Arising from Bacteriopheophytin Reductions in the Photosynthetic Reaction Centers of Rhodobacter sphaeroides
by Gábor Sipka and Péter Maróti
Biomolecules 2024, 14(11), 1367; https://doi.org/10.3390/biom14111367 - 27 Oct 2024
Viewed by 625
Abstract
The pH dependence of the free energy level of the flash-induced primary charge pair P+IA− was determined by a combination of the results from the indirect charge recombination of P+QA− and from the delayed fluorescence [...] Read more.
The pH dependence of the free energy level of the flash-induced primary charge pair P+IA− was determined by a combination of the results from the indirect charge recombination of P+QA− and from the delayed fluorescence of the excited dimer (P*) in the reaction center of the photosynthetic bacterium Rhodobacter sphaeroides, where the native ubiquinone at the primary quinone binding site QA was replaced by low-potential anthraquinone (AQ) derivatives. The following observations were made: (1) The free energy state of P+IA− was pH independent below pH 10 (–370 ± 10 meV relative to that of the excited dimer P*) and showed a remarkable decrease (about 20 meV/pH unit) above pH 10. A part of the dielectric relaxation of the P+IA− charge pair that is not insignificant (about 120 meV) should come from protonation-related changes. (2) The single exponential decay character of the kinetics proves that the protonated/unprotonated P+IA− and P+QA− states are in equilibria and the rate constants of protonation konH +koffH are much larger than those of the charge back reaction kback ~103 s−1. (3) Highly similar pH profiles were measured to determine the free energy states of P+QA− and P+IA−, indicating that the same acidic cluster at around QB should respond to both anionic species. This was supported by model calculations based on anticooperative proton distribution in the cluster with key residues of GluL212, AspL213, AspM17, and GluH173, and the effect of the polarization of the aqueous phase on electrostatic interactions. The larger distance of IA− from the cluster (25.2 Å) compared to that of QA− (14.5 Å) is compensated by a smaller effective dielectric constant (6.5 ± 0.5 and 10.0 ± 0.5, respectively). (4) The P* → P+QA− and IA−QA → IAQA− electron transfers are enthalpy-driven reactions with the exemption of very large (>60%) or negligible entropic contributions in cases of substitution by 2,3-dimethyl-AQ or 1-chloro-AQ, respectively. The possible structural consequences are discussed. Full article
(This article belongs to the Special Issue New Insights into the Membranes of Anoxygenic Phototrophic Bacteria)
►▼ Show Figures

Figure 1

16 pages, 5063 KiB  
Article
Quantitative Analysis of Rhodobacter sphaeroides Storage Organelles via Cryo-Electron Tomography and Light Microscopy
by Daniel Parrell, Joseph Olson, Rachelle A. Lemke, Timothy J. Donohue and Elizabeth R. Wright
Biomolecules 2024, 14(8), 1006; https://doi.org/10.3390/biom14081006 - 14 Aug 2024
Viewed by 1030
Abstract
Bacterial cytoplasmic organelles are diverse and serve many varied purposes. Here, we employed Rhodobacter sphaeroides to investigate the accumulation of carbon and inorganic phosphate in the storage organelles, polyhydroxybutyrate (PHB) and polyphosphate (PP), respectively. Using cryo-electron tomography (cryo-ET), these organelles were observed to [...] Read more.
Bacterial cytoplasmic organelles are diverse and serve many varied purposes. Here, we employed Rhodobacter sphaeroides to investigate the accumulation of carbon and inorganic phosphate in the storage organelles, polyhydroxybutyrate (PHB) and polyphosphate (PP), respectively. Using cryo-electron tomography (cryo-ET), these organelles were observed to increase in size and abundance when growth was arrested by chloramphenicol treatment. The accumulation of PHB and PP was quantified from three-dimensional (3D) segmentations in cryo-tomograms and the analysis of these 3D models. The quantification of PHB using both segmentation analysis and liquid chromatography and mass spectrometry (LCMS) each demonstrated an over 10- to 20-fold accumulation of PHB. The cytoplasmic location of PHB in cells was assessed with fluorescence light microscopy using a PhaP-mNeonGreen fusion-protein construct. The subcellular location and enumeration of these organelles were correlated by comparing the cryo-ET and fluorescence microscopy data. A potential link between PHB and PP localization and possible explanations for co-localization are discussed. Finally, the study of PHB and PP granules, and their accumulation, is discussed in the context of advancing fundamental knowledge about bacterial stress response, the study of renewable sources of bioplastics, and highly energetic compounds. Full article
(This article belongs to the Special Issue New Insights into the Membranes of Anoxygenic Phototrophic Bacteria)
►▼ Show Figures

Graphical abstract

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-2
Back to TopTop