Intrinsic fluorescence spectra of tryptophan, tyrosine and phenyloalanine

Yang, Hui; Xue, Xiao; Zhao, Xuesong; Wu, Yan

doi:10.1117/12.2268397

Cited by 17 publications

(20 citation statements)

References 6 publications

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“…Component 1 includes a putative fluorophore with Ex/Em wavelength pair of 315/430 nm, which could correspond to SA ( Street and Schenk, 1981 ). Component 3 includes Ex/Em wavelength pairs of 245/384 and 265/384 nm, which may correspond to aromatic amino acids and peptides ( Yang et al, 2015 ; Table 1 ).…”

Section: Resultsmentioning

confidence: 99%

“…Phenolics have diverse functions in plants, but one of the most important is their role in plant defense and signaling ( Mandal et al, 2010 ). Hormones are also signaling molecules that can also be found using metabolomics ( Street and Schenk, 1981 ; Li et al, 2009 ; Yang et al, 2015 ). Auxin (e.g., IAA), salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA) are produced in response to physiologic or metabolic changes ( Asami and Nakagawa, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

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Chitosan Induces Plant Hormones and Defenses in Tomato Root Exudates

et al. 2020

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In this work, we use electrophysiological and metabolomic tools to determine the role of chitosan as plant defense elicitor in soil for preventing or manage root pests and diseases sustainably. Root exudates include a wide variety of molecules that plants and root microbiota use to communicate in the rhizosphere. Tomato plants were treated with chitosan. Root exudates from tomato plants were analyzed at 3, 10, 20, and 30 days after planting (dap). We found, using high performance liquid chromatography (HPLC) and excitation emission matrix (EEM) fluorescence, that chitosan induces plant hormones, lipid signaling and defense compounds in tomato root exudates, including phenolics. High doses of chitosan induce membrane depolarization and affect membrane integrity. 1 H-NMR showed the dynamic of exudation, detecting the largest number of signals in 20 dap root exudates. Root exudates from plants irrigated with chitosan inhibit ca. twofold growth kinetics of the tomato root parasitic fungus Fusarium oxysporum f. sp. radicis-lycopersici. and reduced ca. 1.5-fold egg hatching of the root-knot nematode Meloidogyne javanica .

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chitosan Induces Plant Hormones and Defenses in Tomato Root Exudates

et al. 2020

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“…Both phenomena can be related to a main variation of the chemical environment surrounding Tyr residue, which appeared more pronounced for the DAL/N + -rCh-MCD complex. As a matter of fact, the Tyr ABS peak at 227 nm is typically exploited for protein unfolding studies [37], and Tyr fluorescence is predominant with λ ex 275 and λ em peaks at 304 nm [38]. affected by the incubation time, indicating a prompt complexation between MCD and DAL (Table S8, supplementary material).…”

Section: Complexes Stoichiometry and Association Constantmentioning

confidence: 99%

Improvement of Peptide Affinity and Stability by Complexing to Cyclodextrin-Grafted Ammonium Chitosan

et al. 2020

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Cyclodextrin-grafted polymers are attractive biomaterials that could bring together the host–guest complexing capability of pristine cyclodextrin and the pharmaceutical features of the polymeric backbone. The present paper is aimed at characterizing the potential application of ammonium–chitosan grafted with 2-methyl-β-cyclodextrin (N+-rCh-MCD) as the functional macromolecular complexing agent for the oral administration of the neuropeptide dalargin (DAL). Specific NMR characterization procedures, along with UV and fluorescence techniques, as well as biological in vitro assessments have been performed. The results indicate that N+-rCh-MCD forms water-soluble complexes with DAL, with a prevalent involvement of Tyr or Phe over Leu and Ala residues. The association constant of DAL with the polymeric derivative is one order of magnitude higher than that with the pristine cyclodextrin (Ka: 2600 M−1 and 120 M−1, respectively). Additionally, N+-rCh-MCD shields DAL from enzymatic degradation in gastrointestinal in vitro models with a three-fold time delay, suggesting a future pharmaceutical exploitation of the polymeric derivative. Therefore, the greater affinity of N+-rCh-MCD for DAL and its protective effect against enzymatic hydrolysis can be attributed to the synergistic cooperation between cyclodextrin and the polymer, which is realized only when the former is covalently linked to the latter.

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“…Tyr/Phe and Trp fluorescence signals in recombinant INSRα proteins (0.25 μM, aa 1-956, Cat # 11081-H08H, The-moFisher) after incubation with 0.006% DMSO, 1 and 4 μM NPC43 (in PBS buffer solution) were determined by previously described methods [12,26]. The fluorescence spectra of NPC43 at concentrations of 1 and 4 μM in the absence of recombinant INSRα protein were also collected to determine the potential intrinsic fluorescence of NPC43.…”

Section: Tyrosine (Tyr)/phenylalanine (Phe) and Tryptophan (Trp) Fluomentioning

confidence: 99%

“…It has been reported that Tyr/Phe and Trp in proteins have intrinsic fluorescence at emission wavelengths (Em) of 280-304 nm and 330-340 nm [excited at (Ex) 280 nm], respectively, and that the fluorescence intensity of these amino acids is altered if the protein undergoes conformational changes [12,26]. To further investigate whether NPC43 can directly interact with INSRα to elicit conformational changes in INSRα protein, the fluorescence spectra (at Em 250-440 nm/Ex 280 nm) of recombinant INSRα protein after incubation with NPC43 were recorded.…”

Section: In Vitro Interaction Between Npc43 and Insr/ Insr Protein Amentioning

confidence: 99%

Non-peptidyl small molecule, adenosine, 5′-Se-methyl-5′-seleno-, 2′,3′-diacetate, activates insulin receptor and attenuates hyperglycemia in type 2 diabetic Leprdb/db mice

Lan

Lei

Yiannikouris

et al. 2019

Cell. Mol. Life Sci.

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The pathophysiology of type 2 diabetes mellitus (T2D) is characterized by reduced or absent insulin receptor (INSR) responsiveness to its ligand, elevated hepatic glucose output and impaired glucose uptake in peripheral tissues, particularly skeletal muscle. Treatments to reduce hyperglycemia and reestablish normal insulin signaling are much sought after. Any agent which could be orally administered to restore INSR function, in an insulin-independent manner, would have major implications for the management of this global disease. We have discovered a non-peptidyl small molecule, adenosine, 5′-Se-methyl-5′seleno-, 2′,3′-diacetate [referred to as non-peptidyl compound #43 (NPC43)], which restores INSR signaling in the complete absence of insulin. Initial screening of numerous compounds in human HepG2 liver cells revealed that NPC43 significantly inhibited glucose production. The compound was potently anti-hyperglycemic and anti-hyperinsulinemic in vivo, in insulin-resistant T2D Lepr db/db mice, following either acute or chronic treatment by oral gavage and intraperitoneal injection, respectively. The compound acted at the level of INSR and activated it in both liver and skeletal muscle of Lepr db/db mice. In cell culture, the compound activated INSR in both liver and skeletal muscle cells; furthermore, it cooperated with insulin to depress glucose-6-phosphatase catalytic subunit (G6pc) expression and stimulate glucose uptake, respectively. Our results indicated that the compound directly interacted with INSRα, triggering appropriate phosphorylation and activation of the receptor and its downstream targets. Unlike insulin, NPC43 did not activate insulin-like growth factor 1 receptor in either liver or skeletal muscle. We believe this compound represents a potential oral and/or injectable insulin replacement therapy for diabetes and diseases associated with insulin resistance.

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Intrinsic fluorescence spectra of tryptophan, tyrosine and phenyloalanine

Cited by 17 publications

References 6 publications

Chitosan Induces Plant Hormones and Defenses in Tomato Root Exudates

Chitosan Induces Plant Hormones and Defenses in Tomato Root Exudates

Improvement of Peptide Affinity and Stability by Complexing to Cyclodextrin-Grafted Ammonium Chitosan

Non-peptidyl small molecule, adenosine, 5′-Se-methyl-5′-seleno-, 2′,3′-diacetate, activates insulin receptor and attenuates hyperglycemia in type 2 diabetic Leprdb/db mice

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