Conformational and Biological Properties of Partial Sequences of Glucagon

1973 ◽  
Vol 51 (4) ◽  
pp. 243-248 ◽  
Author(s):  
Richard M. Epand ◽  
Vijaylaxmi Grey
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Biological Properties ◽  
In Vitro Assays ◽  
Adenyl Cyclase Activity ◽  
Amino Acid Fragment ◽  
Acid Fragment ◽  
Carboxyl Terminal ◽  
Derivatives Of

We have investigated the properties of derivatives of the 29-amino-acid polypeptide hormone, glucagon, which had varying numbers of amino acids cleaved from the carboxyl terminal portion of the molecule. These derivatives included a 27-amino-acid fragment made by cleavage of the native molecule with cyanogen bromide and a 23-amino-acid fragment made synthetically. We found both of these derivatives capable of stimulating the conversion of ATP to cyclic AMP in in vitro assays using rat liver homogenates. The concentration of these peptides, which were required to produce enhanced adenyl cyclase activity, was higher than that of glucagon, and in the case of the 1–23 derivative it was several orders of magnitude larger. The requirement for higher concentrations of peptide is expected, as removal of a large portion of the total number of amino acids will proportionately decrease the free energy of dissociation of the peptide from the membrane receptor, thus changing the equilibrium constant for binding by several orders of magnitude. Circular dichroism and ultra-centrifuge studies of these peptides, as well as a 21-amino-acid fragment made by cleavage of the native molecule with carboxypeptidase, indicated that the shorter glucagon analogues have structures similar to that of the native molecule although somewhat less ordered.

scholarly journals Feedback Regulation of N Fixation in Frankia-Alnus Symbiosis Through Amino Acids Profiling in Field and Greenhouse Nodules

2020 ◽  
Vol 33 (3) ◽  
pp. 499-508
Author(s):  
Anne-Emmanuelle Hay ◽  
Aude Herrera-Belaroussi ◽  
Marjolaine Rey ◽  
Pascale Fournier ◽  
Philippe Normand ◽  
...  
Keyword(s):  
Amino Acids ◽  
Nitrogen Fixation ◽  
Amino Acid ◽  
Feedback Regulation ◽  
Metabolic Model ◽  
In Vitro Assays ◽  
N Fixation ◽  
Abundance Pattern ◽  
High Level

Symbiosis established between actinorhizal plants and Frankia spp., which are nitrogen-fixing actinobacteria, promotes nodule organogenesis, the site of metabolic exchange. The present study aimed to identify amino acid markers involved in Frankia-Alnus interactions by comparing nodules and associated roots from field and greenhouse samples. Our results revealed a high level of citrulline in all samples, followed by arginine (Arg), aspartate (Asp), glutamate (Glu), γ-amino-n-butyric acid (GABA), and alanine (Ala). Interestingly, the field metabolome approach highlighted more contrasted amino acid patterns between nodules and roots compared with greenhouse samples. Indeed, 12 amino acids had a mean relative abundance significantly different between field nodule and root samples, against only four amino acids in greenhouse samples, underlining the importance of developing “ecometabolome” approaches. In order to monitor the effects on Frankia cells (respiration and nitrogen fixation activities) of amino acid with an abundance pattern evocative of a role in symbiosis, in-vitro assays were performed by supplementing them in nitrogen-free cultures. Amino acids had three types of effects: i) those used by Frankia as nitrogen source (Glu, Gln, Asp), ii) amino acids stimulating both nitrogen fixation and respiration (e.g., Cit, GABA, Ala, valine, Asn), and iii) amino acids triggering a toxic effect (Arg, histidine). In this paper, a N-metabolic model was proposed to discuss how the host plant and bacteria modulate amino acids contents in nodules, leading to a fine regulation sustaining high bacterial nitrogen fixation.

scholarly journals Amino acid derivatives of natural chlorins as a platform for the creation of targeted photosensitizers in oncology

2021 ◽  
Vol 15 (6) ◽  
pp. 16-33
Author(s):  
A. F. Mironov ◽  
P. V. Ostroverkhov ◽  
S. I. Tikhonov ◽  
V. A. Pogorilyy ◽  
N. S. Kirin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Tumor Cells ◽  
Targeted Delivery ◽  
Methionine Sulfoximine ◽  
Amino Acid Derivatives ◽  
Resonance Spectroscopy ◽  
Biochemical Processes ◽  
Derivatives Of

Objectives. This study aims to obtain the amino acid derivatives of chlorophyll a and bacteriochlorophyll a for the targeted delivery of pigments to tumor foci. This will increase biocompatibility and, as a result, reduce toxic side effects. In addition to photodynamic efficiency, an additional cytotoxic effect is expected for the obtained conjugates of photosensitizers (PSs) with amino acids. This is owing to the participation of the latter in intracellular biochemical processes, including interaction with the components of the glutathione antioxidant system, leading to the vulnerability of tumor cells to oxidative stress.Methods. In this work, we have implemented the optimization of the structure of a highly efficient infrared PS based on O-propyloxim-N-propoxybacteriopurpurinimide (DPBP), absorbing at 800 nm and showing photodynamic efficacy for the treatment of deep-seated and pigmented tumors, by introducing L-lysine, L-arginine, methionine sulfoximine (MSO), and buthionine sulfoximine (BSO) methyl esters. The structure of the obtained compounds was proved by mass spectrometry and nuclear magnetic resonance spectroscopy, and the photoinduced cytotoxicity was studied in vitro on the HeLa cell line.Results. Conjugates of DPBP with amino acids and their derivatives, such as lysine, arginine, MSO, and BSO have been prepared. The chelating ability of DPBP conjugate with lysine was shown, and its Sn(IV) complex was obtained.Conclusions. Biological testing of DPBP with MSO and BSO showed a 5–6-fold increase in photoinduced cytotoxicity compared to the parent DPBP PS. Additionally, a high internalization of pigments by tumor cells was found, and the dark cytotoxicity (in the absence of irradiation) of DPBP-MSO and DPBP-BSO increased fourfold compared to the initial DPBP compound. This can be explained by the participation of methionine derivatives in the biochemical processes of the tumor cell.

scholarly journals Anticandida Activity Is Retained in P-113, a 12-Amino-Acid Fragment of Histatin 5

2001 ◽  
Vol 45 (5) ◽  
pp. 1367-1373 ◽  
Author(s):  
David M. Rothstein ◽  
Peter Spacciapoli ◽  
Linh T. Tran ◽  
Tao Xu ◽  
F. Donald Roberts ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Amino Acid ◽  
Oral Candidiasis ◽  
Parent Compound ◽  
Histatin 5 ◽  
Amino Acid Fragment ◽  
Acid Fragment ◽  
Arginine Residues ◽  
Anticandidal Activity

ABSTRACT Through the analysis of a series of 25 peptides composed of various portions of the histatin 5 sequence, we have identified P-113, a 12-amino-acid fragment of histatin 5, as the smallest fragment that retains anticandidal activity comparable to that of the parent compound. Amidation of the P-113 C terminus increased the anticandidal activity of P-113 approximately twofold. The three histidine residues could be exchanged for three hydrophobic residues, with the fragment retaining anticandidal activity. However, the change of two or more of the five basic (lysine and arginine) residues to uncharged residues resulted in a substantial loss of anticandidal activity. A syntheticd-amino-acid analogue, P-113D, was as active againstCandida albicans as the l-amino-acid form. In vitro MIC tests in low-ionic-strength medium showed that P-113 has potent activity against Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis. These results identify P-113 as a potential antimicrobial agent in the treatment of oral candidiasis.

scholarly journals The CaaX Proteases, Afc1p and Rce1p, Have Overlapping but Distinct Substrate Specificities

2000 ◽  
Vol 20 (12) ◽  
pp. 4381-4392 ◽  
Author(s):  
Cynthia Evans Trueblood ◽  
Victor L. Boyartchuk ◽  
Elizabeth A. Picologlou ◽  
David Rozema ◽  
C. Dale Poulter ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Single Amino Acid ◽  
In Vitro Assays ◽  
Sequence Motif ◽  
Amino Acid Substitutions ◽  
In The Wild

ABSTRACT Many proteins that contain a carboxyl-terminal CaaX sequence motif, including Ras and yeast a-factor, undergo a series of sequential posttranslational processing steps. Following the initial prenylation of the cysteine, the three C-terminal amino acids are proteolytically removed, and the newly formed prenylcysteine is carboxymethylated. The specific amino acids that comprise the CaaX sequence influence whether the protein can be prenylated and proteolyzed. In this study, we evaluated processing of a-factor variants with all possible single amino acid substitutions at either the a1, the a2, or the X position of the a-factor Ca1a2X sequence, CVIA. The substrate specificity of the two known yeast CaaX proteases, Afc1p and Rce1p, was investigated in vivo. Both Afc1p and Rce1p were able to proteolyze a-factor with A, V, L, I, C, or M at the a1 position, V, L, I, C, or M at the a2 position, or any amino acid at the X position that was acceptable for prenylation of the cysteine. Eight additional a-factor variants with a1 substitutions were proteolyzed by Rce1p but not by Afc1p. In contrast, Afc1p was able to proteolyze additional a-factor variants that Rce1p may not be able to proteolyze. In vitro assays indicated that farnesylation was compromised or undetectable for 11 a-factor variants that produced no detectable halo in the wild-type AFC1 RCE1 strain. The isolation of mutations in RCE1 that improved proteolysis of a-factor-CAMQ, indicated that amino acid substitutions E139K, F189L, and Q201R in Rce1p affected its substrate specificity.

scholarly journals Biological Properties of a Novel Follicle-Stimulating Hormone/Human Chorionic Gonadotropin Chimeric Gonadotropin

Endocrinology ◽  
2006 ◽  
Vol 147 (9) ◽  
pp. 4205-4212 ◽  
Author(s):  
Louise M. Garone ◽  
Elena Ammannati ◽  
Theresa S. Brush ◽  
David J. Fischer ◽  
Enrico Gillio Tos ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Biological Properties ◽  
Glycoprotein Hormone ◽  
Α Subunit ◽  
Recombinant Human Fsh

A chimeric recombinant human gonadotropin, termed C3, demonstrates both follitropic and lutropic bioactivities. The α-subunit construct for C3 is comprised of the recombinant wild-type human glycoprotein hormone α-subunit. The β-subunit DNA construct for C3 encodes residues 1–145 from human chorionic gonadotropin (hCG)-β with the exceptions that FSHβ amino acid 88 (D) is substituted for hCGβ amino acid 94 (R) and FSHβ amino acids 95–108 (TVRGLGPSYCSFGE) are substituted for hCGβ amino acids 101–114 (GGPKDHPLTCDDPR). C3 is a potent FSH and LH agonist able to bind and to signal through FSH and LH receptors in vitro. In in vivo bioassays optimized to quantify each type of activity, C3 was found to have lutropin and follitropin potencies at levels similar to those of recombinant human LH and recombinant human FSH, respectively. In immature rats, C3 was sufficient to support the maturation of normal ovarian follicles. Moreover, a significant portion of follicles matured by C3 ruptured in response to an ovulatory hCG stimulus and gave rise to morphologically normal oocytes. Furthermore, a low dose of C3 promoted weight gain in the rodent uterus, suggesting it also supported preparation for implantation without histological evidence of excessive luteinization of the ovary. In summary, the biological properties of C3 indicate that its chimeric nature has resulted in a fully functional, dual-acting human gonadotropin.

scholarly journals FRUCTOSE-AMINO ACIDS IN LIVER: STIMULI OF AMINO ACID INCORPORATION IN VITRO

1955 ◽  
Vol 215 (1) ◽  
pp. 111-124 ◽  
Author(s):  
Henry Borsook ◽  
Adolph Abrams ◽  
Peter H. Lowy
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Incorporation ◽  
Acid Incorporation

scholarly journals Transdermal Delivery Systems for Ibuprofen and Ibuprofen Modified with Amino Acids Alkyl Esters Based on Bacterial Cellulose

2021 ◽  
Vol 22 (12) ◽  
pp. 6252
Author(s):  
Paula Ossowicz-Rupniewska ◽  
Rafał Rakoczy ◽  
Anna Nowak ◽  
Maciej Konopacki ◽  
Joanna Klebeko ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Bacterial Cellulose ◽  
Acid Ester ◽  
Active Pharmaceutical Ingredient ◽  
Amino Acid Ester ◽  
Isopropyl Ester ◽  
Isopropyl Esters ◽  
Transdermal Application

The potential of bacterial cellulose as a carrier for the transport of ibuprofen (a typical example of non-steroidal anti-inflammatory drugs) through the skin was investigated. Ibuprofen and its amino acid ester salts-loaded BC membranes were prepared through a simple methodology and characterized in terms of structure and morphology. Two salts of amino acid isopropyl esters were used in the research, namely L-valine isopropyl ester ibuprofenate ([ValOiPr][IBU]) and L-leucine isopropyl ester ibuprofenate ([LeuOiPr][IBU]). [LeuOiPr][IBU] is a new compound; therefore, it has been fully characterized and its identity confirmed. For all membranes obtained the surface morphology, tensile mechanical properties, active compound dissolution assays, and permeation and skin accumulation studies of API (active pharmaceutical ingredient) were determined. The obtained membranes were very homogeneous. In vitro diffusion studies with Franz cells were conducted using pig epidermal membranes, and showed that the incorporation of ibuprofen in BC membranes provided lower permeation rates to those obtained with amino acids ester salts of ibuprofen. This release profile together with the ease of application and the simple preparation and assembly of the drug-loaded membranes indicates the enormous potentialities of using BC membranes for transdermal application of ibuprofen in the form of amino acid ester salts.

scholarly journals Novel Amino Acid Derivatives of Quinolines as Potential Antibacterial and Fluorophore Agents

2020 ◽  
Vol 88 (4) ◽  
pp. 57
Author(s):  
Oussama Moussaoui ◽  
Rajendra Bhadane ◽  
Riham Sghyar ◽  
El Mestafa El Hadrami ◽  
Soukaina El Amrani ◽  
...  
Keyword(s):  
Amino Acid ◽  
Methyl Esters ◽  
Amino Acid Derivatives ◽  
Bacterial Strains ◽  
Fluorescent Properties ◽  
Topoisomerase Iv ◽  
Microdilution Method ◽  
Hydrolysis Of ◽  
Derivatives Of

A new series of amino acid derivatives of quinolines was synthesized through the hydrolysis of amino acid methyl esters of quinoline carboxamides with alkali hydroxide. The compounds were purified on silica gel by column chromatography and further characterized by TLC, NMR and ESI-TOF mass spectrometry. All compounds were screened for in vitro antimicrobial activity against different bacterial strains using the microdilution method. Most of the synthesized amino acid-quinolines show more potent or equipotent inhibitory action against the tested bacteria than their correspond esters. In addition, many of them exhibit fluorescent properties and could possibly be utilized as fluorophores. Molecular docking and simulation studies of the compounds at putative bacterial target enzymes suggest that the antimicrobial potency of these synthesized analogues could be due to enzyme inhibition via their favorable binding at the fluoroquinolone binding site at the GyrA subunit of DNA gyrase and/or the ParC subunit of topoisomerase-IV.

scholarly journals Phylogenetic analysis and predicted functional effect of protein mutations of E6 and E7 HPV16 strains isolated in Indonesia

2015 ◽  
Vol 24 (4) ◽  
pp. 197-205
Author(s):  
Dwi Wulandari ◽  
Lisnawati Rachmadi ◽  
Tjahjani M. Sudiro
Keyword(s):  
Amino Acids ◽  
Phylogenetic Analysis ◽  
Amino Acid ◽  
Asian American ◽  
Protein Function ◽  
Single Amino Acid ◽  
Hpv16 E6 ◽  
E6 And E7 ◽  
Neutral Mutations

Background: E6 and E7 are oncoproteins of HPV16. Natural amino acid variation in HPV16 E6 can alter its carcinogenic potential. The aim of this study was to analyze phylogenetically E6 and E7 genes and proteins of HPV16 from Indonesia and predict the effects of single amino acid substitution on protein function. This analysis could be used to reduce time, effort, and research cost as initial screening in selection of protein or isolates to be tested in vitro or in vivo.Methods: In this study, E6 and E7 gene sequences were obtained from 12 samples of  Indonesian isolates, which  were compared with HPV16R (prototype) and 6 standard isolates in the category of European (E), Asian (As), Asian-American (AA), African-1 (Af-1), African-2 (Af-2), and North American (NA) branch from Genbank. Bioedit v.7.0.0 was used to analyze the composition and substitution of single amino acids. Phylogenetic analysis of E6 and E7 genes and proteins was performed using Clustal X (1.81) and NJPLOT softwares. Effects of single amino acid substitutions on protein function of E6 and E7 were analysed by SNAP.Results: Java variants and isolate ui66* belonged to European branch, while the others belonged to Asian and African branches. Twelve changes of amino acids were found in E6 and one in E7 proteins. SNAP analysis showed two non neutral mutations, i.e. R10I and C63G in E6 proteins. R10I mutations were found in Af-2 genotype (AF472509) and Indonesian isolates (Af2*), while C63G mutation was found only in Af2*.Conclusion: E6 proteins of HPV16 variants were more variable than E7. SNAP analysis showed that only E6 protein of African-2 branch had functional differences compared to HPV16R.

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