Nitrogen scavenging from amino acids and peptides in the model alga Chlamydomonas reinhardtii. The role of extracellular l-amino oxidase

The role of the two processing sites in the precursor of the small subunit (SS) of ribulose-1,5-bisphosphate carboxylase/oxygenase (pSS) of Chlamydomonas reinhardtii was studied by introducing mutations at the cleavage sites for the stromal processing peptidases SPP-1 and SPP-2, which hydrolyse wild-type pSS (20.6kDa) to an intermediate-sized product iSS (18.3kDa) and to the mature SS (16.3kDa), respectively. The mutations introduced into cDNA resulted in exchange of (a) two amino acids flanking processing site 1, or (b) one or (c) both amino acids flanking processing site 2. Mutation (a) prevented pSS from being processed at site 1 but not from cleavage at site 2. Mutation (c) abolished the action of SPP-2 but not SPP-1. When pSS with mutation (c) was imported into isolated chloroplasts, iSS accumulated while SS formation was abolished. However, mature SS was produced even in the absence of iSS synthesis (mutation a). Import of pSS bearing mutation (b), which only partially inhibited processing at the SPP-2 site, slowed the rate of SS formation down whereas iSS and some slightly smaller derivatives accumulated. These experiments suggested that in Chlamydomonas processing of pSS can occur in two steps, whereby the first step is facultative. The same three mutations were studied in vivo after transformation of SS-deficient C. reinhardtii T60-3 with mutated genomic DNA. Growth and photosynthesis was as in control transformants, except for the slower-growing transformants (mutation c) where no mature SS was immuno-detected. However, pSS fragments with molecular masses between those of iSS and SS were present even in the ribulose-1,5-bisphosphate carboxylase/oxygenase holoenzyme.

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Chemical Transmission in the Brain: The Role of Amines, Amino Acids and Peptides, Proceedings of the 12th International Summer School of Brain Research, held at the Royal Netherlands Academy of Arts and Sciences

10.1016/s0079-6123(08)x6121-7 ◽

1982 ◽

Keyword(s):

Amino Acids ◽

Summer School ◽

Brain Research ◽

Arts And Sciences ◽

Royal Netherlands Academy ◽

The Brain ◽

International Summer School ◽

Chemical Transmission

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Role of amino acids and micronutrients on biosynthesis of spiramycins

Journal of Chemical Technology & Biotechnology ◽

10.1002/jctb.280310126 ◽

1981 ◽

Vol 31 (1) ◽

pp. 189-193 ◽

Cited By ~ 1

Author(s):

Mohamed A. Ashy ◽

Abd El-Galil ◽

M. Khalil ◽

Abou-Zeid A. Abou-Zeid

Keyword(s):

Amino Acids

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Directive Effect of Chain Length in Modulating Peptide Nano-assemblies

Protein and Peptide Letters ◽

10.2174/0929866527666200224114627 ◽

2020 ◽

Vol 27 (9) ◽

pp. 923-929

Author(s):

Gaurav Pandey ◽

Prem Prakash Das ◽

Vibin Ramakrishnan

Keyword(s):

Electron Microscopy ◽

Amino Acids ◽

Light Scattering ◽

Chain Length ◽

Self Assembly ◽

The Self ◽

Ionic Charge ◽

Self Assembling ◽

Biophysical Techniques

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.

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10 THE ROLE OF DIETARY L-SERINE IN THE REGULATION OF INTESTINAL MUCUS BARRIER DURING INFLAMMATION

Inflammatory Bowel Diseases ◽

10.1093/ibd/zaa010.110 ◽

2020 ◽

Vol 26 (Supplement_1) ◽

pp. S42-S42

Author(s):

Kohei Sugihara ◽

Nobuhiko Kamada

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Gut Microbiota ◽

Control Diet ◽

Bacterial Strains ◽

Germ Free ◽

Intestinal Mucus ◽

Gnotobiotic Mice ◽

Mucus Barrier

Abstract Background Recent accumulating evidence suggests that amino acids have crucial roles in the maintenance of intestinal homeostasis. In inflammatory bowel disease (IBD), amino acid metabolism is changed in both host and the gut microbiota. Among amino acids, L-serine plays a central role in several metabolic processes that are essential for the growth and survival of both mammalian and bacterial cells. However, the role of L-serine in intestinal homeostasis and IBD remains incompletely understood. In this study, we investigated the effect of dietary L-serine on intestinal inflammation in a murine model of colitis. Methods Specific pathogen-free (SPF) mice were fed either a control diet (amino acid-based diet) or an L-serine-deficient diet (SDD). Colitis was induced by the treatment of dextran sodium sulfate (DSS). The gut microbiome was analyzed by 16S rRNA sequencing. We also evaluate the effect of dietary L-serine in germ-free mice and gnotobiotic mice that were colonized by a consortium of non-mucolytic bacterial strains or the consortium plus mucolytic bacterial strains. Results We found that the SDD exacerbated experimental colitis in SPF mice. However, the severity of colitis in SDD-fed mice was comparable to control diet-fed mice in germ-free condition, suggesting that the gut microbiota is required for exacerbation of colitis caused by the restriction of dietary L-serine. The gut microbiome analysis revealed that dietary L-serine restriction fosters the blooms of a mucus-degrading bacterium Akkermansia muciniphila and adherent-invasive Escherichia coli in the inflamed gut. Consistent with the expansion of mucolytic bacteria, SDD-fed mice showed a loss of the intestinal mucus layer. Dysfunction of the mucus barrier resulted in increased intestinal permeability, thereby leading to bacterial translocation to the intestinal mucosa, which subsequently increased the severity of colitis. The increased intestinal permeability and subsequent bacterial translocation were observed in SDD-fed gnotobiotic mice that colonized by mucolytic bacteria. In contrast, dietary L-serine restriction did not alter intestinal barrier integrity in gnotobiotic mice that colonized only by non-mucolytic bacteria. Conclusion Our results suggest that dietary L-serine regulates the integrity of the intestinal mucus barrier during inflammation by limiting the expansion of mucus degrading bacteria.

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Reconstitution in Proteoliposomes of the Recombinant Human Riboflavin Transporter 2 (SLC52A2) Overexpressed in E. coli

International Journal of Molecular Sciences ◽

10.3390/ijms20184416 ◽

2019 ◽

Vol 20 (18) ◽

pp. 4416 ◽

Cited By ~ 2

Author(s):

Lara Console ◽

Maria Tolomeo ◽

Matilde Colella ◽

Maria Barile ◽

Cesare Indiveri

Keyword(s):

Cardiovascular Disease ◽

Amino Acids ◽

Risk Factor ◽

Biologically Active ◽

Suitable Model ◽

Native Protein ◽

E Coli ◽

Few Data ◽

Riboflavin Transport

Background: the SLC52A2 gene encodes for the riboflavin transporter 2 (RFVT2). This transporter is ubiquitously expressed. It mediates the transport of Riboflavin across cell membranes. Riboflavin plays a crucial role in cells since its biologically active forms, FMN and FAD, are essential for the metabolism of carbohydrates, amino acids, and lipids. Mutation of the Riboflavin transporters is a risk factor for anemia, cancer, cardiovascular disease, neurodegeneration. Inborn mutations of SLC52A2 are associated with Brown-Vialetto-van Laere syndrome, a rare neurological disorder characterized by infancy onset. In spite of the important metabolic and physio/pathological role of this transporter few data are available on its function and regulation. Methods: the human recombinant RFVT2 has been overexpressed in E. coli, purified and reconstituted into proteoliposomes in order to characterize its activity following the [3H]Riboflavin transport. Results: the recombinant hRFVT2 showed a Km of 0.26 ± 0.07 µM and was inhibited by lumiflavin, FMN and Mg2+. The Riboflavin uptake was also regulated by Ca2+. The native protein extracted from fibroblast and reconstituted in proteoliposomes also showed inhibition by FMN and lumiflavin. Conclusions: proteoliposomes represent a suitable model to assay the RFVT2 function. It will be useful for screening the mutation of RFVT2.

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The role of conserved amino acids in substrate binding and discrimination by photolyase

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)85476-5 ◽

1993 ◽

Vol 268 (22) ◽

pp. 16717-16724

Author(s):

M.E. Baer ◽

G.B. Sancar

Keyword(s):

Amino Acids ◽

Substrate Binding ◽

Conserved Amino Acids

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Adiponectin: Structure, Physiological Functions, Role in Diseases, and Effects of Nutrition

Nutrients ◽

10.3390/nu13041180 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1180

Author(s):

Kayvan Khoramipour ◽

Karim Chamari ◽

Amirhosein Ahmadi Hekmatikar ◽

Amirhosein Ziyaiyan ◽

Shima Taherkhani ◽

...

Keyword(s):

Cardiovascular Disease ◽

Amino Acids ◽

Molecular Weight ◽

Energy Regulation ◽

Treatment Interventions ◽

Adipose Tissues ◽

Physiological Functions ◽

Cellular Events ◽

Healthy Nutrition

Adiponectin (a protein consisting of 244 amino acids and characterized by a molecular weight of 28 kDa) is a cytokine that is secreted from adipose tissues (adipokine). Available evidence suggests that adiponectin is involved in a variety of physiological functions, molecular and cellular events, including lipid metabolism, energy regulation, immune response and inflammation, and insulin sensitivity. It has a protective effect on neurons and neural stem cells. Adiponectin levels have been reported to be negatively correlated with cancer, cardiovascular disease, and diabetes, and shown to be affected (i.e., significantly increased) by proper healthy nutrition. The present review comprehensively overviews the role of adiponectin in a range of diseases, showing that it can be used as a biomarker for diagnosing these disorders as well as a target for monitoring the effectiveness of preventive and treatment interventions.

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