Computational Quantification of the Physicochemical Effects of Heme Distortion: Redox Control in the Reaction Center Cytochrome Subunit of Blastochloris viridis

In an attempt to identify polysaccharide components in thin sections of D. maydis, procedures were employed such that a PAS localization could be carried out. Three different fixatives were evaluated ie. glutaraldehyde, formaldehyde and paraformaldehyde. These were used in conjunction with periodic acid (PA), thiosemicarbazide(TSC), and osmium tetroxide(Os) to localize polysaccharides in V. maydis using a pre-embedded reaction procedure. Polysaccharide localization is based on the oxidation of vic-glycol groups by PA, and the binding of TSC as a selective reaction center for the formation of osmium black. The reaction product is sufficiently electron opaque, insoluble in lipids, not altered when tissue is embedded, and has a fine amorphous character.

Download Full-text

The Singlet-Triplet Splitting of the Primary Radical Pair in the Bacterial Photosynthetic Reaction Center*

Zeitschrift für Physikalische Chemie ◽

10.1524/zpch.1992.1.part_1.193 ◽

1992 ◽

Vol 1 (Part_1) ◽

pp. 193-208

Author(s):

M. Bixon ◽

J. Jortner ◽

M. E. Michel-Beyerle

Keyword(s):

Reaction Center ◽

Radical Pair ◽

Photosynthetic Reaction Center ◽

Primary Radical ◽

Triplet Splitting ◽

Primary Radical Pair ◽

Bacterial Photosynthetic Reaction Center

Download Full-text

Nomenclature Abstract for Blastochloris viridis (Drews and Giesbrecht 1966) Hiraishi 1997 emend. Hördt et al. 2020.

The NamesforLife Abstracts ◽

10.1601/nm.1539 ◽

2003 ◽

Author(s):

Charles Thomas Parker ◽

Sarah Wigley ◽

George M Garrity

Keyword(s):

Blastochloris Viridis

Download Full-text

Computational Investigation of the Asymmetry in Photosynthetic Reaction Center Models from First Principles

10.26434/chemrxiv.11980119.v1 ◽

2020 ◽

Author(s):

Denis Artiukhin ◽

Patrick Eschenbach ◽

Johannes Neugebauer

Keyword(s):

Spin Density ◽

Reaction Center ◽

Density Functional ◽

Photosynthetic Reaction Center ◽

Chem Phys ◽

Molecular Structures ◽

Error Characteristic ◽

Molecular Systems ◽

Density Distributions ◽

The Asymmetry

We present a computational analysis of the asymmetry in reaction center models of photosystem I, photosystem II, and bacteria from Synechococcus elongatus, Thermococcus vulcanus, and Rhodobacter sphaeroides, respectively. The recently developed FDE-diab methodology [J. Chem. Phys., 148 (2018), 214104] allowed us to effectively avoid the spin-density overdelocalization error characteristic for standard Kohn–Sham Density Functional Theory and to reliably calculate spin-density distributions and electronic couplings for a number of molecular systems ranging from dimeric models in vacuum to large protein including up to about 2000 atoms. The calculated spin densities showed a good agreement with available experimental results and were used to validate reaction center models reported in the literature. We demonstrated that the applied theoretical approach is very sensitive to changes in molecular structures and relative orientation of molecules. This makes FDE-diab a valuable tool for electronic structure calculations of large photosynthetic models effectively complementing the existing experimental techniques.

Download Full-text