scholarly journals Constrained Dipeptide Surrogates: 5- and 7-Hydroxy Indolizidin-2-one Amino Acid Synthesis from Iodolactonization of Dehydro-2,8-diamino Azelates

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 67
Author(s):  
Ramakotaiah Mulamreddy ◽  
William D. Lubell
Keyword(s):  
Amino Acids ◽  
Acid Synthesis ◽  
Ring System ◽  
Dihedral Angles ◽  
Type Ii ◽  
Amino Ester ◽  
Amino Acid Synthesis ◽  
X Ray ◽  
Amino Esters ◽  
Peptide Mimicry

The constrained dipeptide surrogates 5- and 7-hydroxy indolizidin-2-one N-(Boc)amino acids have been synthesized from L-serine as a chiral educt. A linear precursor ∆4-unsaturated (2S,8S)-2,8-bis[N-(Boc)amino]azelic acid was prepared in five steps from L-serine. Although epoxidation and dihydroxylation pathways gave mixtures of hydroxy indolizidin-2-one diastereomers, iodolactonization of the ∆4-azelate stereoselectively delivered a lactone iodide from which separable (5S)- and (7S)-hydroxy indolizidin-2-one N-(Boc)amino esters were synthesized by sequences featuring intramolecular iodide displacement and lactam formation. X-ray analysis of the (7S)-hydroxy indolizidin-2-one N-(Boc)amino ester indicated that the backbone dihedral angles embedded in the bicyclic ring system resembled those of the central residues of an ideal type II’ β-turn indicating the potential for peptide mimicry.

scholarly journals Petasis vs. Strecker Amino Acid Synthesis: Convergence, Divergence and Opportunities in Organic Synthesis

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1707
Author(s):  
Wayiza Masamba
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Organic Synthesis ◽  
Acid Synthesis ◽  
Physical Sciences ◽  
Amino Acid Synthesis

α-Amino acids find widespread applications in various areas of life and physical sciences. Their syntheses are carried out by a multitude of protocols, of which Petasis and Strecker reactions have emerged as the most straightforward and most widely used. Both reactions are three-component reactions using the same starting materials, except the nucleophilic species. The differences and similarities between these two important reactions are highlighted in this review.

scholarly journals New aspects of amino acid metabolism in cancer

2019 ◽  
Vol 122 (2) ◽  
pp. 150-156 ◽  
Author(s):  
Lisa Vettore ◽  
Rebecca L. Westbrook ◽  
Daniel A. Tennant
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cancer Cells ◽  
Cancer Metabolism ◽  
Acid Synthesis ◽  
Response To Therapy ◽  
Direct Role ◽  
Amino Acid Synthesis ◽  
Metabolic Coupling ◽  
Abundant Supply

AbstractAn abundant supply of amino acids is important for cancers to sustain their proliferative drive. Alongside their direct role as substrates for protein synthesis, they can have roles in energy generation, driving the synthesis of nucleosides and maintenance of cellular redox homoeostasis. As cancer cells exist within a complex and often nutrient-poor microenvironment, they sometimes exist as part of a metabolic community, forming relationships that can be both symbiotic and parasitic. Indeed, this is particularly evident in cancers that are auxotrophic for particular amino acids. This review discusses the stromal/cancer cell relationship, by using examples to illustrate a number of different ways in which cancer cells can rely on and contribute to their microenvironment – both as a stable network and in response to therapy. In addition, it examines situations when amino acid synthesis is driven through metabolic coupling to other reactions, and synthesis is in excess of the cancer cell’s proliferative demand. Finally, it highlights the understudied area of non-proteinogenic amino acids in cancer metabolism and their potential role.

scholarly journals New Enzymatic Method of Chiral Amino Acid Synthesis by Dynamic Kinetic Resolution of Amino Acid Amides: Use of Stereoselective Amino Acid Amidases in the Presence of α-Amino-ε-Caprolactam Racemase

2007 ◽  
Vol 73 (16) ◽  
pp. 5370-5373 ◽  
Author(s):  
Shigenori Yamaguchi ◽  
Hidenobu Komeda ◽  
Yasuhisa Asano
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Kinetic Resolution ◽  
Acid Synthesis ◽  
Enzymatic Method ◽  
Ochrobactrum Anthropi ◽  
Dynamic Kinetic Resolution ◽  
Amino Acid Synthesis

ABSTRACT d- and l-amino acids were produced from l- and d-amino acid amides by d-aminopeptidase from Ochrobactrum anthropi C1-38 and l-amino acid amidase from Pseudomonas azotoformans IAM 1603, respectively, in the presence of α-amino-ε-caprolactam racemase from Achromobacter obae as the catalyst by dynamic kinetic resolution of amino acid amides.

scholarly journals Biosynthesis of Amino Acids in Xanthomonas oryzae pv. oryzae Is Essential to Its Pathogenicity

2019 ◽  
Vol 7 (12) ◽  
pp. 693 ◽  
Author(s):  
Ting Li ◽  
Zhaohong Zhan ◽  
Yunuan Lin ◽  
Maojuan Lin ◽  
Qingbiao Xie ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Bacterial Growth ◽  
Acid Synthesis ◽  
Xanthomonas Oryzae ◽  
Host Responses ◽  
Amino Acid Synthesis ◽  
Rice Bacterial Blight ◽  
Nutrient Environment ◽  
Blight Disease

Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice bacterial blight disease, which causes a large reduction in rice production. The successful interaction of pathogens and plants requires a particular nutrient environment that allows pathogen growth and the initiation of both pathogen and host responses. Amino acid synthesis is essential for bacterial growth when bacteria encounter amino acid-deficient environments, but the effects of amino acid synthesis on Xoo pathogenicity are unclear. Here, we systemically deleted the essential genes (leuB, leuC, leuD, ilvC, thrC, hisD, trpC, argH, metB, and aspC) involved in the synthesis of different amino acids and analyzed the effects of these mutations on Xoo virulence. Our results showed that leucine, isoleucine, valine, histidine, threonine, arginine, tryptophan, and cysteine syntheses are essential to Xoo infection. We further studied the role of leucine in the interaction between pathogens and hosts and found that leucine could stimulate some virulence-related responses and regulate Xoo pathogenicity. Our findings highlight that amino acids not only act as nutrients for bacterial growth but also play essential roles in the Xoo and rice interaction.

scholarly journals Mechanism of De Novo Branched-Chain Amino Acid Synthesis as an Alternative Electron Sink in Hypoxic Aspergillus nidulans Cells

2010 ◽  
Vol 76 (5) ◽  
pp. 1507-1515 ◽  
Author(s):  
Motoyuki Shimizu ◽  
Tatsuya Fujii ◽  
Shunsuke Masuo ◽  
Naoki Takaya
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspergillus Nidulans ◽  
De Novo ◽  
Acid Synthesis ◽  
Branched Chain Amino Acids ◽  
Amino Acid Synthesis ◽  
Lactate Dehydrogenase Activity ◽  
Branched Chain Amino Acid ◽  
Branched Chain

ABSTRACT Although branched-chain amino acids are synthesized as building blocks of proteins, we found that the fungus Aspergillus nidulans excretes them into the culture medium under hypoxia. The transcription of predicted genes for synthesizing branched-chain amino acids was upregulated by hypoxia. A knockout strain of the gene encoding the large subunit of acetohydroxy acid synthase (AHAS), which catalyzes the initial reaction of the synthesis, required branched-chain amino acids for growth and excreted very little of them. Pyruvate, a substrate for AHAS, increased the amount of hypoxic excretion in the wild-type strain. These results indicated that the fungus responds to hypoxia by synthesizing branched-chain amino acids via a de novo mechanism. We also found that the small subunit of AHAS regulated hypoxic branched-chain amino acid production as well as cellular AHAS activity. The AHAS knockout resulted in higher ratios of NADH/NAD+ and NADPH/NADP+ under hypoxia, indicating that the branched-chain amino acid synthesis contributed to NAD+ and NADP+ regeneration. The production of branched-chain amino acids and the hypoxic induction of involved genes were partly repressed in the presence of glucose, where cells produced ethanol and lactate and increased levels of lactate dehydrogenase activity. These indicated that hypoxic branched-chain amino acid synthesis is a unique alternative mechanism that functions in the absence of glucose-to-ethanol/lactate fermentation and oxygen respiration.

scholarly journals Photosynthetic assimilation of CO2 regulates TOR activity

2022 ◽  
Vol 119 (2) ◽  
pp. e2115261119
Author(s):  
Manuel J. Mallén-Ponce ◽  
María Esther Pérez-Pérez ◽  
José L. Crespo
Keyword(s):  
Amino Acids ◽  
Carbon Assimilation ◽  
Acid Synthesis ◽  
Tor Signaling ◽  
Amino Acid Synthesis ◽  
Photosynthetic Organisms ◽  
Endogenous Level ◽  
Tor Kinase ◽  
Photosynthetic Assimilation ◽  
Stimulation Of

The target of rapamycin (TOR) kinase is a master regulator that integrates nutrient signals to promote cell growth in all eukaryotes. It is well established that amino acids and glucose are major regulators of TOR signaling in yeast and metazoan, but whether and how TOR responds to carbon availability in photosynthetic organisms is less understood. In this study, we showed that photosynthetic assimilation of CO2 by the Calvin–Benson–Bassham (CBB) cycle regulates TOR activity in the model single-celled microalga Chlamydomonas reinhardtii. Stimulation of CO2 fixation boosted TOR activity, whereas inhibition of the CBB cycle and photosynthesis down-regulated TOR. We uncovered a tight link between TOR activity and the endogenous level of a set of amino acids including Ala, Glu, Gln, Leu, and Val through the modulation of CO2 fixation and the use of amino acid synthesis inhibitors. Moreover, the finding that the Chlamydomonas starch-deficient mutant sta6 displayed disproportionate TOR activity and high levels of most amino acids, particularly Gln, further connected carbon assimilation and amino acids to TOR signaling. Thus, our results showed that CO2 fixation regulates TOR signaling, likely through the synthesis of key amino acids.

Notizen: Die Kristallstruktur des Mauritins-A / The Crystal Structure of Mauritine-A

1976 ◽  
Vol 31 (2) ◽  
pp. 279-280 ◽  
Author(s):  
A. Kibfel ◽  
G. Will ◽  
R. Tschesche ◽  
H. Wilhelm
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Ring System ◽  
Membered Ring ◽  
Trans Configuration ◽  
X Ray Diffraction ◽  
Uv Spectrum ◽  
X Ray ◽  
Cyclopeptide Alkaloid ◽  
Hydroxy Proline

The constitution and conformation of the known cyclopeptide alkaloid mauritine-A were determined by X-ray diffraction methods. All amino acids belong to the L-series, 3-hydroxy proline has trans-configuration. As indicated by the UV-spectrum, the 14-membered ring system is considerably strained.

scholarly journals A Novelmeso-Diaminopimelate Dehydrogenase from Symbiobacterium thermophilum: Overexpression, Characterization, and Potential for d-Amino Acid Synthesis

2012 ◽  
Vol 78 (24) ◽  
pp. 8595-8600 ◽  
Author(s):  
Xiuzhen Gao ◽  
Xi Chen ◽  
Weidong Liu ◽  
Jinhui Feng ◽  
Qiaqing Wu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Enantiomeric Excess ◽  
Acid Synthesis ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Gene Encoding ◽  
Amino Acid Synthesis ◽  
Content Type

ABSTRACTmeso-Diaminopimelate dehydrogenase (meso-DAPDH) is an NADP+-dependent enzyme which catalyzes the reversible oxidative deamination on thed-configuration ofmeso-2,6-diaminopimelate to producel-2-amino-6-oxopimelate. In this study, the gene encoding ameso-diaminopimelate dehydrogenase fromSymbiobacterium thermophilumwas cloned and expressed inEscherichia coli. In addition to the native substratemeso-2,6-diaminopimelate, the purified enzyme also showed activity towardd-alanine,d-valine, andd-lysine. This enzyme catalyzed the reductive amination of 2-keto acids such as pyruvic acid to generated-amino acids in up to 99% conversion and 99% enantiomeric excess. Sincemeso-diaminopimelate dehydrogenases are known to be specific tomeso-2,6-diaminopimelate, this is a unique wild-typemeso-diaminopimelate dehydrogenase with a more relaxed substrate specificity and potential ford-amino acid synthesis. The enzyme is the most stablemeso-diaminopimelate dehydrogenase reported to now. Two amino acid residues (F146 and M152) in the substrate binding sites ofS. thermophilum meso-DAPDH different from the sequences of other knownmeso-DAPDHs were replaced with the conserved amino acids in othermeso-DAPDHs, and assay of wild-type and mutant enzyme activities revealed that F146 and M152 are not critical in determining the enzyme's substrate specificity. The high thermostability and relaxed substrate profile ofS. thermophilum meso-DAPDH warrant it as an excellent starting enzyme for creating effectived-amino acid dehydrogenases by protein engineering.

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