scholarly journals Crystal Structure of Chloroplastic Thioredoxin f2 from Chlamydomonas reinhardtii Reveals Distinct Surface Properties

Antioxidants ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 171 ◽  
Author(s):  
Stéphane Lemaire ◽  
Daniele Tedesco ◽  
Pierre Crozet ◽  
Laure Michelet ◽  
Simona Fermani ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Active Sites ◽  
Carbon Fixation ◽  
Disulfide Reduction ◽  
Photosynthetic Eukaryotes ◽  
Multimeric Complex ◽  
Different Types ◽  
Multigenic Family ◽  
Living Organisms ◽  
Protein Disulfide

Protein disulfide reduction by thioredoxins (TRXs) controls the conformation of enzyme active sites and their multimeric complex formation. TRXs are small oxidoreductases that are broadly conserved in all living organisms. In photosynthetic eukaryotes, TRXs form a large multigenic family, and they have been classified in different types: f, m, x, y, and z types are chloroplastic, while o and h types are located in mitochondria and cytosol. In the model unicellular alga Chlamydomonas reinhardtii, the TRX family contains seven types, with f- and h-types represented by two isozymes. Type-f TRXs interact specifically with targets in the chloroplast, controlling photosynthetic carbon fixation by the Calvin–Benson cycle. We solved the crystal structures of TRX f2 and TRX h1 from C. reinhardtii. The systematic comparison of their atomic features revealed a specific conserved electropositive crown around the active site of TRX f, complementary to the electronegative surface of their targets. We postulate that this surface provides specificity to each type of TRX.

On the Adsorption of Aspartate Derivatives to Calcite Surfaces in Aqueous Environment

2020 ◽  
Author(s):  
Robert Stepic ◽  
Lara Jurković ◽  
Ksenia Klementyeva ◽  
Marko Ukrainczyk ◽  
Matija Gredičak ◽  
...  
Keyword(s):  
Active Sites ◽  
Realistic Model ◽  
Binding Energies ◽  
Inhibition Mechanism ◽  
Aqueous Environment ◽  
Binding Modes ◽  
Carboxylate Groups ◽  
Dissolved Ions ◽  
Living Organisms ◽  
Dynamics Simulations

In many living organisms, biomolecules interact favorably with various surfaces of calcium carbonate. In this work, we have considered the interactions of aspartate (Asp) derivatives, as models of complex biomolecules, with calcite. Using kinetic growth experiments, we have investigated the inhibition of calcite growth by Asp, Asp2 and Asp3.This entailed the determination of a step-pinning growth regime as well as the evaluation of the adsorption constants and binding free energies for the three species to calcite crystals. These latter values are compared to free energy profiles obtained from fully atomistic molecular dynamics simulations. When using a flat (104) calcite surface in the models, the measured trend of binding energies is poorly reproduced. However, a more realistic model comprised of a surface with an island containing edges and corners, yields binding energies that compare very well with experiments. Surprisingly, we find that most binding modes involve the positively charged, ammonium group. Moreover, while attachment of the negatively charged carboxylate groups is also frequently observed, it is always balanced by the aqueous solvation of an equal or greater number of carboxylates. These effects are observed on all calcite features including edges and corners, the latter being associated with dominant affinities to Asp derivatives. As these features are also precisely the active sites for crystal growth, the experimental and theoretical results point strongly to a growth inhibition mechanism whereby these sites become blocked, preventing further attachment of dissolved ions and halting further growth.

scholarly journals Conjugate of Thiol and Guanidyl Units with Oligoethylene Glycol Linkage for Manipulation of Oxidative Protein Folding

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 879
Author(s):  
Shunsuke Okada ◽  
Motonori Matsusaki ◽  
Masaki Okumura ◽  
Takahiro Muraoka
Keyword(s):  
Protein Folding ◽  
Active Sites ◽  
Biological Process ◽  
Thiol Group ◽  
Native Conformation ◽  
Thiol Compounds ◽  
Oxidative Protein Folding ◽  
Redox Active ◽  
A Cell ◽  
Protein Disulfide

Oxidative protein folding is a biological process to obtain a native conformation of a protein through disulfide-bond formation between cysteine residues. In a cell, disulfide-catalysts such as protein disulfide isomerase promote the oxidative protein folding. Inspired by the active sites of the disulfide-catalysts, synthetic redox-active thiol compounds have been developed, which have shown significant promotion of the folding processes. In our previous study, coupling effects of a thiol group and guanidyl unit on the folding promotion were reported. Herein, we investigated the influences of a spacer between the thiol group and guanidyl unit. A conjugate between thiol and guanidyl units with a diethylene glycol spacer (GdnDEG-SH) showed lower folding promotion effect compared to the thiol–guanidyl conjugate without the spacer (GdnSH). Lower acidity and a more reductive property of the thiol group of GdnDEG-SH compared to those of GdnSH likely resulted in the reduced efficiency of the folding promotion. Thus, the spacer between the thiol and guanidyl groups is critical for the promotion of oxidative protein folding.

BIOMEDICAL RESEARCH PAYS OFF

PEDIATRICS ◽  
1977 ◽  
Vol 59 (6) ◽  
pp. 832-832
Author(s):  
J. H. Comroe ◽  
R. D. Dripps
Keyword(s):  
Research And Development ◽  
Biomedical Research ◽  
Basic Research ◽  
The Other ◽  
Human Diseases ◽  
Different Types ◽  
Living Organisms

Our analysis showed . . . 41% of all work judged to be essential for later clinical advance was not clinically oriented at the time it was done. The scientists responsible for these key articles sought knowledge for the sake of knowledge. . . . Our data show that clinical advance requires different types of research and development and not one to the exclusion of the other. . . . Our data compel us to conclude (1) that a generous portion of the nation's biomedical research dollar should be used to identify and then provide long term support for creative scientists whose main goal is to learn how living organisms function, without regard to the immediate relation of their research to specific human diseases; and (2) that basic research, as we have defined it, pays off in terms of key discoveries almost twice as handsomely as other types of research and development combined.

Engineering the CBB cycle and hydrogen utilization pathway of Ralstonia eutropha H16 for improved autotrophic growth and PHB production

2020 ◽  
Author(s):  
Zhongkang Li ◽  
Muzi Hu ◽  
Bin Xiong ◽  
Dongdong Zhao ◽  
Chunzhi Zhang ◽  
...  
Keyword(s):  
Carbon Fixation ◽  
Ralstonia Eutropha ◽  
Biological Research ◽  
Industrial Biotechnology ◽  
Cell Factory ◽  
Autotrophic Growth ◽  
Microbial Cell Factory ◽  
Knock Out ◽  
Ralstonia Eutropha H16 ◽  
Living Organisms

Abstract CO 2 is fixed by all living organisms with an autotrophic metabolism, among which the Calvin-Benson-Bassham ( CBB) cycle is the most important and widespread carbon fixation pathway. Thus, studying and engineering the CBB cycle with the associated energy providing pathways to increase the CO 2 fixation efficiency of cells is an important subject of biological research with significant application potential. In this work, the autotrophic microbe Ralstonia eutropha H16 was selected as a research platform for CBB cycle optimization engineering. By knocking out either CBB operon genes on the operon or mega-plasmid of R. eutropha , we found that both CBB operons were active and contributed almost equally to the carbon fixation process. With similar knock-out experiments, we found while both soluble and membrane-bound hydrogenases (SH and MBH), belonging to the energy providing hydrogenase module, were f unctional d uring autotrophic growth of R. eutropha. And SH played a more significant role. By introducing a heterologous cyanobacterial RuBisCO with the endogenous GroES/EL chaperone system and RbcX, the culture OD 600 of engineered strain increased 89.15% after 72 hours of autotrophic growth, indicating cyanobacterial RuBisCO with a higher activity was functional in R. eutropha and improved upon original CBB pathway. Meanwhile, expression of hydrogenases were optimized by modulating the expression of MBH and SH, which could further increase the R. eutropha H16 culture OD 600 to 93.4% at 72 hours. Moreover, the autotrophic yield of its major industrially relevant product, polyhydroxybutyrate (PHB), was increased by 99.71%. To our best knowledge, this is the first report of successfully engineering the CBB pathway of R. eutropha for improved activity , and is one of only a few cases where the efficiency of CO 2 assimilation pathway was improved. Our work demonstrates that R. eutropha is an extremely useful platform for studying and engineering the CBB for applications in more important organisms, such as agricultural crops, and a potential microbial cell factory to develop industrial biotechnology for sequestrating CO 2 .

Evidences of the presence of different types of active sites for the oxygen reduction reaction with Fe/N/C based catalysts

2016 ◽  
Vol 327 ◽  
pp. 204-211 ◽  
Author(s):  
Francisco J. Pérez-Alonso ◽  
Carlota Domínguez ◽  
Shaeel A. Al-Thabaiti ◽  
Abdulrahman O. Al-Youbi ◽  
Mohamed Abdel Salam ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Active Sites ◽  
Reduction Reaction ◽  
Different Types

scholarly journals Odor Markers of Poetical Speech of the Beginning of the XX Century

2019 ◽  
pp. 44-61
Author(s):  
Oleksandr Cherevchenko
Keyword(s):  
National Language ◽  
Silver Age ◽  
New Words ◽  
Vital Functions ◽  
Ethnic Language ◽  
The World ◽  
Different Types ◽  
Basic Functions ◽  
Points Of View ◽  
Living Organisms

The article deals with an attempt to characterize a smell in human knowledge, analyzed the points of view of different scientists concerning this problem, considered odor markers of the artistic text as components of united system of verbal and non verbal individual resources aimed at forming different types of subtext. The olfactory feeling occupies the special place in the vital functions of man. They arose up one of the first, next to taste, which provided the living organisms two basic functions: feed and reproduction. However, in the process of evolution, olfactory feelings experienced the biggest changes European poetry of the beginning of XX century is interesting in its aspiration to create a new poetical speech that is why the attention is adhered to odor instruments, when the smell became an expression of the esthetical subtext. Odor content of the poetical speech of the XX century is one of the most important tools of forming content deepness of the text meaning, disclosure of the palette of meanings. The research is based on the material of poetry of representatives of Silver age and Ukrainian neoclassicists. The research proves that the most dynamic is lexical system of the language which helps to show ethnic language map of the world in artistic text. It studies the evolution of an individual author’s nomination in the poetic creativity of M. Rylsky, M. Zerov, Y. Klen, M. Dray-Hmara, P. Fylypovych, A. Block, N. Gumilov, A. Akchmatova, V. Maiakovski, S. Jesenin, V. Chlebnikov, O. Mandelshtam, M. Zvietaieva, V. Briusov and others. The paper examines the semantic-derivative structure of innovations of odor lexems, classifies the most numerous lexical and semantic groups of new words for identifying smell, and defines typical signs of odorous lexemes that represent the specific national language and poetic view of the world. Materials of the research can be used in teaching such subjects as “Modern Ukrainian Literary Language (lexicology, phraseology, lexicography)”, “Stylistics and Culture of the Ukrainian Language”, “Rhetoric and Linguistic Analysis of Artistic Text”, as well as special courses on ethnolinguistics, linguopoetics; for writing chapters devoted to the study of trope units, in textbooks and manuals; in lexicographic practice when compiling dictionaries of the writer’s language.

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