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1.
We have tested the hypothesis that activation of the insulin receptor tyrosine kinase is due to autophosphorylation of tyrosines 1146, 1150 and 1151 within a putative autoinhibitory domain. A synthetic peptide corresponding to residues 1134–1162, with tyrosines substituted by alanine or phenylalanine, of the insulin receptor subunit was tested for its inhibitory potency and specificity towards the tyrosine kinase activity. This synthetic peptide gave inhibition of the insulin receptor tyrosine kinase autophosphorylation and phosphorylation of the exogenous substrate poly(Glu, Tyr) with an approximate IC50 of 100 M. Inhibition appeared to be independent of the concentrations of insulin or the substrate poly(Glu, Tyr) but was decreased by increasing concentrations of ATP. This same peptide also inhibited the EGF receptor tyrosine kinase but not a serine/threonine protein kinase. These results are consistent with the hypothesis that this autophosphorylation domain contains an autoinhibitory sequence. (Mol Cell Biochem120: 103–110, 1993)Abbreviations IR
Insulin Receptor
- SDS/PAGE
Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis
- CaM
Calmodulin
- HEPES
4-(2-Hydroxyethyl)-Piperazineethane-Sulfonic Acid
- DMEM
Dulbecco's Modified Eagle' Medium
- PMSF
Phenylmethyl-Sulfonyl Fluoride
- HPLC
High Performance Liquid Chromatography
- PKC
Protein Kinase C
- PKI
Inhibitory Peptide for cAMP-Kinase
- CaMK II
Ca2+/Calmodulin-Dependent Protein Kinase II
- CaN A
A Subunit of Calcineurin 相似文献
2.
Morten P. Oksvold Nina Marie Pedersen Lise Forfang Erlend B. Smeland 《FEBS letters》2012,586(20):3575-3581
Cycloheximide is the most common protein synthesis inhibitor, and is believed to specifically inhibit the cytoplasmic protein synthesis. Here we demonstrate that cycloheximide induces internalization and redistribution of EGF receptor to early endosomes in HeLa cells independent of receptor tyrosine phosphorylation, but dependent on p38 MAPK activity. Degradation of EGF receptor or its downstream effectors was not observed. EGF-induced activation of ERK1/2 was inhibited upon pre-treatment with cycloheximide, but did not activate JNK. The observed effects of treatment with cycloheximide alone are significant and therefore results involving the use of cycloheximide for inhibition of protein synthesis must be interpreted with caution.
Structured summary of protein interactions
EEA1 and EGFRcolocalize by fluorescence microscopy (View interaction). 相似文献3.
Pandya V Jain M Chakrabarti G Soni H Parmar B Chaugule B Patel J Joshi J Joshi N Rath A Raviya M Shaikh M Sairam KV Patel H Patel P 《Bioorganic & medicinal chemistry letters》2011,21(19):5701-5706
Two novel series of 5-nitro-2-phenoxybenzoic acid derivatives are designed as potent PAI-1 inhibitors using hybridization and conformational restriction strategy in the tiplaxtinin and piperazine chemo types. The lead compounds 5a, 6c, and 6e exhibited potent PAI-1 inhibitory activity and favorable oral bioavailability in the rodents. 相似文献
4.
I. S. Smirnova I. V. Gonchar A. N. Shatrova N. N. Nikolskii E. B. Burova 《Cell and Tissue Biology》2010,4(4):372-379
Previously, we showed that hydrogen peroxide (H2O2) induces the ligand-independent activation (transactivation) of EGF receptor in various cells overexpressing EGF receptor.
In the present work, the mechanism of H2O2-induced EGF receptor transactivation was studied in A431 human epidermoid carcinoma cells. The autophosphorylation of the
EGF receptor at tyrosine residues 1045, 1068, 1148, 1173, as well as the phosphorylation of tyrosine 845, was demonstrated.
It has been shown that the tyrosine phosphorylation of the EGF receptor does not involve autophosphorylation at tyrosine 992.
The blockage of the function of metalloproteases with broad-spectrum inhibitor GM6001 suppressed H2O2-induced phosphorylation of EGF receptor, which suggests the dependence of the transactivation on metalloprotease activity.
To elucidate the possible role of EGF receptor agonists in its activation, antibodies against HB-EGF and TGF-α were used.
H2O2-induced EGF receptor phosphorylation was inhibited by HB-EGF, but not TGF-α, a neutralizing antibody. We believe that the
mechanism of transactivation of EGF receptor during oxidative stress is realized via autophosphorylation and includes HB-EGF
as a necessary component of signal transduction mediated by metalloprotease activity. 相似文献
5.
Jinggong Liu Weilin Liu Hu Ge Jinbo Gao Qingqing He Lijuan Su Jun Xu Lian-quan Gu Zhi-shu Huang Ding Li 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014
Background
Farnesyl pyrophosphate synthase (FPPS) is a key regulatory enzyme in the biosynthesis of cholesterol and in the post-translational modification of signaling proteins. It has been reported that non-bisphosphonate FPPS inhibitors targeting its allosteric binding pocket are potentially important for the development of promising anti-cancer drugs.Methods
The following methods were used: organic syntheses of non-bisphosphonate quinoline derivatives, enzyme inhibition studies, fluorescence titration assays, synergistic effect studies of quinoline derivatives with zoledronate, ITC studies for the binding of FPPS with quinoline derivatives, NMR-based HAP binding assays, molecular modeling studies, fluorescence imaging assay and MTT assays.Results
We report our syntheses of a series of quinoline derivatives as new FPPS inhibitors possibly targeting the allosteric site of the enzyme. Compound 6b showed potent inhibition to FPPS without significant hydroxyapatite binding affinity. The compound showed synergistic inhibitory effect with active-site inhibitor zoledronate. ITC experiment confirmed the good binding effect of compound 6b to FPPS, and further indicated the binding ratio of 1:1. Molecular modeling studies showed that 6b could possibly bind to the allosteric binding pocket of the enzyme. The fluorescence microscopy indicated that these compounds could get into cancer cells.Conclusions
Our results showed that quinoline derivative 6b could become a new lead compound for further optimization for cancer treatment.General significance
The traditional FPPS active-site inhibitors bisphosphonates show poor membrane permeability to tumor cells, due to their strong polarity. The development of new non-bisphosphonate FPPS inhibitors with good cell membrane permeability is potentially important. 相似文献6.
Lauren R.H. Krumpe Toshiyuki Mori 《International journal of peptide research and therapeutics》2006,12(1):79-91
Monoclonal antibodies have been successfully utilized as cancer-targeting therapeutics and diagnostics, but the efficacies
of these treatments are limited in part by the size of the molecules and non-specific uptake by the reticuloendothelial system.
Peptides are much smaller molecules that can specifically target cancer cells and as such may alleviate complications with
antibody therapy. Although many endogenous and exogenous peptides have been developed into clinical therapeutics, only a subset
of these consists of cancer-targeting peptides. Combinatorial biological libraries such as bacteriophage-displayed peptide
libraries are a resource of potential ligands for various cancer-related molecular targets. Target-binding peptides can be
affinity selected from complex mixtures of billions of displayed peptides on phage and further enriched through the biopanning
process. Various cancer-specific ligands have been isolated by in vitro, in vivo, and ex vivo screening methods. As several peptides derived from phage-displayed peptide library screenings have been developed into therapeutics
in current clinical trials, which validates peptide-targeting potential, the use of phage display to identify cancer-targeting
therapeutics should be further exploited.
相似文献
Toshiyuki MoriEmail: |
7.
Evgenija A. Djurendi? Marija N. Saka? Janoš J. ?anadi Gordana M. Bogdanovi? 《Steroids》2009,74(12):983-1081
Starting from 3β-hydroxy-17-oxo-16,17-secoandrost-5-ene-16-nitrile (1), the new 16,17-secoandrostane derivatives 4-9 were synthesized. On the other hand, 3β-hydroxy-17-oxa-d-homoandrost-5-ene-16-one (10) yielded the new d-homo derivatives 12, 13 and 15. In vitro antiproliferative activity of selected compounds against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER−, MDA-MB-231, prostate cancer AR−, PC-3, and normal fetal lung fibroblasts, MRC-5) was evaluated. Compounds 3 and 12 showed strong antiproliferative activity against PC-3 cells, the IC50 values being 2 μM and 0.55 μM, respectively. Compounds 6 (10 μM) and 14 (9 μM) showed moderate activity against MDA-MB-231 cells. The synthesized compounds 1-3, 5-8, 10 and 12-15 were not toxic to normal fetal lung fibroblasts cells, MRC-5. 相似文献
8.
Villalonga-Barber C Meligova AK Alexi X Steele BR Kouzinos CE Screttas CG Katsanou ES Micha-Screttas M Alexis MN 《Bioorganic & medicinal chemistry》2011,19(1):339-351
We have synthesized a series of new (E) stilbenoid derivatives containing hydroxy groups at ring positions identical or similar to those of trans-resveratrol and bearing one or two bulky electron donating groups ortho to 4′-OH and we have evaluated their neuroprotective activity using glutamate-challenged HT22 hippocampal neurons to model oxidative stress-induced neuronal cell death. The most active derivatives, 5-{(E)-2-[3,5-bis(1-ethylpropyl)-4-hydroxyphenyl]ethenyl}-1,3-benzenediol (2), 5-[(E)-2-(3,5-di-tert-butyl-4-hydroxyphenylethenyl)]-1,3-benzenediol (4) and 5-{(1E,3E)-4-[3,5-bis(1-ethylpropyl)-4-hydroxyphenyl]-1,3-butadienyl}-1,3-benzenediol (6), had EC50 values of 30, 45 and 12 nM, respectively, and were ca. 100 to 400-fold more potent than resveratrol. Derivatives 2, 4 and 6 lacked cytotoxic activity against HT22 cells and estrogen receptor agonist or antagonist activity in estrogen response element-dependent gene expression and in estrogen-dependent proliferation of MCF-7 human breast cancer cells. In addition, they were incapable of interfering with aryl hydrocarbon receptor-mediated xenobiotic response element-dependent gene expression. Derivatives 2, 4 and 6 might assist in the development of lead candidates against oxidative stress-driven neurodegenerative diseases that will not increase endocrine cancer risk nor affect drug activation and detoxification mechanisms. 相似文献
9.
J. Féthière R. Graihle L. Larose K. Babinski H. Ong A. De Léan 《Molecular and cellular biochemistry》1993,124(1):11-16
The differential distribution of natriuretic peptide receptor subtypes and their distinct properties were assessed in mammalian cellular models which were screened for their ability to produce cGMP upon stimulation by different natriuretic peptides. The ANF-R1A receptor subtype was distinguished by its selective activation by atrial natriuretic factor (ANF) while the ANF-R1C was characterized by preferential stimulation by C-type natriuretic peptide (CNP). AT-t20 pituitary cells, bovine adrenal chromaffin cells, and NIH-3T3 fibroblasts mainly express the ANF-R1C receptor subtype. Other cell lines such as PC12, RASM and GH3 express significant but varying amounts of both ANF-R1A and ANF-R1C subtypes. A10 and NIH cells which express high density of ANF-R2 receptor subtype, also demonstrate a higher sensitivity to CNP over ANF suggesting that they express significant amounts of ANF-R1C. Studies of the regulation by ATP of guanylyl cyclase activity indicate that both ANF-R1A and ANF-R1C subtypes are modulated in the same manner. In the presence of Mn2+, ATP inhibits the CNP-stimulated guanylyl cyclase activity while in the presence of Mg2+ adenine nucleotides potentiate the stimulation by CNP. In addition, we show that like the ANF-R1A, the ANF-R1C guanylyl cyclase activity can be regulated by phosphorylation since preincubation with TPA or FKL attenuates the subsequent stimulation by CNP in cultured cells. The results presented demonstrate that specific cell types express distinct natriuretic peptide receptor subtypes and also that the newly characterized ANF-R1C subtype is regulated by ATP and serine/threonine kinases in the same way as the ANF-R1A subtype.Abbreviation ANF
atrial natriuretic factor
- BNP
brain natriuretic peptide
- CNP
C-type natriuretic peptide
- ATP
adenosine-5-triphosphate
- IBMX
3-isobutyl-1-methylxanthine
- TPA
12-O-tetradecanoyl-phorbol-13-acetate
- FKL
forskolin
- PKC
calcium-phospholipid-dependent protein kinase
- PKA
cAMP-dependent protein kinase
- PKG
cGMP-dependent protein kinase
- C-ANF
[Cys116]-ANF-(102-116)-NH2
- CC
chromaffin cells 相似文献
10.
Mei-Yan Wei Cui-Fang Wang Kai-Ling Wang Pei-Yuan Qian Chang-Yun Wang Chang-Lun Shao 《Marine biotechnology (New York, N.Y.)》2017,19(4):372-378
A series of 30 sclerotioramine derivatives (2–31) of the natural compound, (+)-sclerotiorin (1), has been successfully semi-synthesized by a one-step reaction with high yields (up to 80%). The structures of these new derivatives were established by extensive spectroscopic methods and single-crystal X-ray diffraction analysis for 3, 6, and 10. (+)-Sclerotiorin (1) and its semisynthetic derivatives (2–31) were evaluated for their antifouling activity. Most of them except 6, 7, 8, 12, and 28 showed potent antifouling activity against the larval settlement of the barnacle Balanus amphitrite. More interestingly, most of the aromatic amino-derivatives (13–17, 19–21, 23, 25–27, and 29–31) showed strong antifouling activity; however, only two aliphatic amino-derivatives (5 and 10) had the activity. 相似文献
11.
Stellatin (4), isolated from Dysophylla stellata is a cyclooxygenase (COX) inhibitor. The present study reports the synthesis and biological evaluation of new stellatin derivatives for COX-1, COX-2 inhibitory and anti-inflammatory activities. Eight derivatives showed more pronounced COX-2 inhibition than stellatin and, 17 and 21 exhibited the highest COX-2 inhibition. They also exhibited the significant anti-inflammatory activity in TPA-induced mouse ear edema assay and their anti-inflammatory effects were more than that of stellatin and indomethacin at 0.5 mg/ear. The derivatives were further evaluated for antioxidant activity wherein 16 and 17 showed potent free radical scavenging activity against DPPH and ABTS radicals. Molecular docking study revealed the binding orientations of stellatin and its derivatives into the active sites of COX-1 and COX-2 and thereby helps to design the potent inhibitors. 相似文献
12.
Sergio Valente Ilaria Lepore Carmela Dell'Aversana Maria Tardugno Sabrina Castellano Gianluca Sbardella Stefano Tomassi Salvatore Di Maro Ettore Novellino Roberto Di Santo Roberta Costi Lucia Altucci Antonello Mai 《Biochimie》2012
Chemical manipulations undertaken on some bis(bromo- and dibromo-phenol) compounds previously reported by us as wide-spectrum epigenetic inhibitors let us to identify bis (bromo- and dibromo-methoxyphenyl) derivatives highly selective for PR-SET7 and EZH2 (compounds 4, 5, 9, and 10). Western blot analyses were carried out in U937 cells to determine the effects of such compounds on the methyl marks related to the tested enzymes (H3K4me1, H3K9me2, H4H20me1, and H3K27me3). The 1,5-bis(3-bromo-4-methoxyphenyl)penta-1,4-dien-3-one 4 (EC50 vs EZH2 = 74.9 μM), tested in U937 cells at 50 μM, induced massive cell death and 28% of granulocytic differentiation, highlighting the potential use of EZH2 inhibitors in cancer. 相似文献
13.
Jennifer L. Macdonald-Obermann Linda J. Pike 《The Journal of biological chemistry》2009,284(20):13570-13576
We have previously shown that the binding of epidermal growth factor (EGF)
to its receptor can best be described by a model that involves negative
cooperativity in an aggregating system (Macdonald, J. L., and Pike, L. J.
(2008) Proc. Natl. Acad. Sci. U. S. A. 105, 112–117). However,
despite the fact that biochemical analyses indicate that EGF induces
dimerization of its receptor, the binding data provided no evidence for
positive linkage between EGF binding and dimer assembly. By analyzing the
binding of EGF to a number of receptor mutants, we now report that in naive,
unphosphorylated EGF receptors, ligand binding is positively linked to
receptor dimerization but the linkage is abolished upon autophosphorylation of
the receptor. Both phosphorylated and unphosphorylated EGF receptors exhibit
negative cooperativity, indicating that mechanistically, cooperativity is
distinct from the phenomenon of linkage. Nonetheless, both the positive
linkage and the negative cooperativity observed in EGF binding require the
presence of the intracellular juxtamembrane domain. This indicates the
existence of inside-out signaling in the EGF receptor system. The
intracellular juxtamembrane domain has previously been shown to be required
for the activation of the EGF receptor tyrosine kinase (Thiel, K. W., and
Carpenter, G. (2007) Proc. Natl. Acad. Sci. U. S. A. 104,
19238–19243). Our experiments expand the role of this domain to include
the allosteric control of ligand binding by the extracellular domain.The EGF2 receptor
is a tyrosine kinase composed of an ∼620-amino-acid extracellular domain
that recognizes and binds EGF, a single pass α-helical transmembrane
domain, and an intracellular tyrosine kinase domain, encompassing roughly
residues 685–950 (1). In
addition, the receptor contains an ∼230-amino-acid-long C-terminal tail
that contains the bulk of the sites of receptor autophosphorylation
(2–4).
An intracellular juxtamembrane domain of about 40 residues connects the
transmembrane domain to the kinase domain and has been shown to be crucial in
the allosteric activation of the EGF receptor kinase
(5,
6).In the membrane, the EGF receptor exists as a monomer, but a wealth of data
indicate that the binding of EGF induces the formation of EGF receptor dimers
(7–10).
Dimerization appears to be mediated in large part by the extracellular domain
of the receptor, which is comprised of four subdomains, designated I through
IV. X-ray crystallography data suggest that in the absence of ligand, the
extracellular domain is held in a closed configuration through the interaction
of loops or arms that extend from the backs of subdomains II and IV
(11). Upon binding of EGF,
this intramolecular tether is released, allowing the receptor to adopt an open
conformation in which EGF is tightly bound between subdomains I and III. In
this configuration, the “dimerization arm” that was previously
involved in tethering the receptor closed mediates the formation of a
back-to-back EGF receptor dimer
(12,
13).Analyses of the binding of 125I-EGF to its receptor have
invariably resulted in concave up Scatchard plots that have been interpreted
as indicating the presence of two classes of EGF binding sites. However, we
have recently used global analysis of the binding of 125I-EGF to
cells expressing increasing levels of EGF receptors to show that EGF binding
is best described by a model involving negative cooperativity in an
aggregating system (14) (see
Fig. 6). Ligand binding is
negatively cooperative if the binding of ligand to the first site on a dimer
reduces the affinity of the ligand for binding to the second site on the
dimer.Open in a separate windowFIGURE 6.Model for the binding of EGF to its receptor. Circles
represent receptor subunits. E represents a molecule of EGF. The
equilibrium association constants are written above or beside the reaction to
which they apply.The concept of cooperativity only applies to existing dimers. It does not
relate to the effect of ligand on the assembly or disassembly of those dimers.
The effect of ligand on the formation of receptor dimers is captured in the
concept of linkage (15,
16). If ligand binding is
positively linked to dimer formation, then ligand promotes the assembly of
receptor dimers. In a monomer-dimer equilibrium, positive linkage arises when
a ligand binds with higher affinity to the first site on the dimer than to the
monomer. Under these circumstances, the ligand will preferentially bind to the
dimer, shifting the equilibrium in favor of the dimeric species. In the case
of the EGF receptor, biochemical data suggest that EGF induces receptor
dimerization; however, evidence for positive linkage in binding studies has
been lacking.By analyzing the binding of 125I-EGF to cells expressing various
EGF receptor mutants, we now report that in naive, unphosphorylated EGF
receptors, ligand binding is, in fact, positively linked to receptor
dimerization. Autophosphorylation of the EGF receptor abolishes the positive
linkage that is present during the initial phase of the ligand binding
reaction. Negative cooperativity is present in both the phosphorylated and the
non-phosphorylated states of the receptor. Structure-function analyses
demonstrate that both cooperativity and linkage are lost when the EGF receptor
is truncated immediately after the transmembrane domain. However, both forms
of regulation are restored in receptors that include the additional 40 amino
acids that correspond to the intracellular juxtamembrane domain. These data
expand the role of the intracellular juxtamembrane domain to include the
allosteric regulation of EGF binding by the extracellular domain and
demonstrate the presence of inside-out signaling in the EGF receptor
system. 相似文献
14.
Štefica Horvat 《Carbohydrate research》2010,345(3):377-7903
The formation of glycosylation products in model systems consisting of d-glucuronic acid (GlcA) and lysine-containing peptides, such as Lys-Gly-Gly-Phe-Leu (1), Gly-Lys-Gly-Phe-Leu (4) and Ac-Gly-Lys-Gly-Phe-Leu (6), was examined to evaluate the site specificity as well as the extent and nature of the modification. Peptides were reacted with GlcA either in solution or under dry-heating conditions. From the incubations performed in solution (MeOH), the corresponding (1-deoxy-d-fructofuranos-1-yluronic acid)-peptide derivatives (Amadori compounds) were isolated. Whereas reaction of 1 resulted in the formation of mono-glycosylated Amadori compound 2 with the sugar moiety attached to the Nε-amino group of the Lys residue and its di-glycosylated analogue 3, exposure of 4 to GlcA afforded only di-glycosylated peptide 5. From the incubation of GlcA with Ac-Gly-Lys-Gly-Phe-Leu (6) performed under mild dry-heating conditions (50 °C) in an environment of 75% relative humidity, besides Amadori compound 7, two new Maillard reaction products were isolated that contained 3-hydroxypyridinium (8) and 3-hydroxy-picolinic acid moiety (9). The mechanism for the formation of pyridinium products is discussed. 相似文献
15.
Atrial and brain natriuretic peptides share binding sites on cultured cells from the rat trachea 总被引:1,自引:0,他引:1
Summary We examined the distribution of binding sites for alpha-atrial natriuretic peptide (125I-ANP1–28) and the recently discovered porcine brain natriuretic peptide (125I-pBNP) on immunocytochemically identified cells in dissociated culture preparations of the rat trachea. Specific binding sites for both 125I-ANP1–28 and 125I-pBNP were evenly distributed over distinet subpopulations of smooth muscle myosin-like immunoreactive muscle cells, fibronectin-like immunoreactive fibroblasts and S-100-like immunoreactive glial cells. Neither keratin-like immunoreactive epithelial cells nor protein gene product 9.5-like immunoreactive paratracheal neurones expressed natriuretic peptide binding sites, although autoradiographically labelled glial cells were seen in close association with both neuronal cell bodies and neurites. The binding of each radiolabelled peptide was abolished by the inclusion of either excess (1 M) unlabelled rat ANP or excess unlabelled porcine BNP, suggesting that ANP and BNP share binding sites in the trachea. Furthermore, the ring-deleted analogue, Des-[Gln18, Ser19, Gly20, Leu21, Gly22]-ANF4–23-NH2, strongly competed for specific 125I-ANP1–28 and 125I-pBNP binding sites in the tracheal cultures; this suggests that virtually all binding sites were of the clearance (ANP-C or ANF-R2) receptor subtype. 相似文献
16.
Modulation of immunoreactive endothelin-1 (IR-ET-1) production by vasoactive substances was investigated in cultured endothelial cells (EC) derived from capillaries and microvessels of human brain. Peptides, catecholamines, thrombin, protein kinase C-activating phorbol ester, and calcium ionophore enhanced the secretion of IR-ET-1. The known vasoconstrictive peptides, angiotensin II (Ang II) and arginine-vasopressin (AVP) dose-dependently stimulated the endothelial secretion of IR-ET-1. The angiotensin and vasopressin-inducible production of IR-ET-1 was completely inhibited by their respective receptor antagonists [Sar1, Ala8]-angiotensin II and [1–6 (-mercapto-,-cyclopentamethylene propionic acid), 2-O-methyl-tyrosine]. The results indicate that the peptide-stimulated secretion of IR-ET-1 is receptor-mediated in EC which have specific angiotensin II and arginine-vasopressin receptors. These findings represent the first demonstration of IR-ET-1 production by capillary and microvascular endothelium of human brain. 相似文献
17.
Paul F. Agris Marie T. Marchbank Winnell Newman Richard Guenther Phyllis Ingram Jacinda Swallow Piotr Mucha Agnieszka Szyk Piotr Rekowski Elena Peletskaya Susan L. Deutscher 《Journal of Protein Chemistry》1999,18(4):425-435
Peptides that bind either U1 small nuclear RNA (U1 snRNA) or the anticodon stem and loop of yeast tRNAPhe (tRNA
AC
Phe
) were selected from a random-sequence, 15-amino acid bacteriophage display library. An experimental system, including an affinity selection method, was designed to identify primary RNA-binding peptide sequences without bias to known amino acid sequences and without incorporating nonspecific binding of the anionic RNA backbone. Nitrocellulose binding assays were used to evaluate the binding of RNA by peptide-displaying bacteriophage. Amino acid sequences of RNA-binding bacteriophage were determined from the foreign insert DNA sequences, and peptides corresponding to the RNA-binding bacteriophage inserts were chemically synthesized. Peptide affinities for the RNAs (K
d 0.1–5.0 M) were analyzed successfully using fluorescence and circular dichroism spectroscopies. These methodologies demonstrate the feasibility of rapidly identifying, isolating, and initiating the analyses of small peptides that bind to RNAs in an effort to define better the chemistry, structure, and function of protein–RNA complexes. 相似文献
18.
Regioselective facile one-pot synthesis of 16 different sugar-based quinoline, naphthyridine, and xanthone derivatives is reported. The compounds are characterized by NMR spectroscopy and elemental analysis. The β-Anomeric form of the sugar moiety was identified from 1H NMR studies. Antimicrobial studies of these sugar-heterocyclic derivatives, 3a, 3b, 3f, 5c, 7a, 7b, and 7c show excellent activity against different microbes. 相似文献
19.
K. V. Martynova L. A. Andreeva P. A. Klimova Yu. G. Kirillova V. P. Shevchenko I. Yu. Nagaev S. I. Shram V. I. Shvets N. F. Myasoedov 《Russian Journal of Bioorganic Chemistry》2009,35(2):150-156
A synthetic scheme for preparation of (Gly-Pro) n , (Pro-Gly) n (n = 2, 3), and (Pro-Gly-Pro) n (n = 1, 2) peptides was elaborated. The effect of the synthesized peptides and the Gly-Pro and Pro-Gly dipeptides on survival of cultured cells of PC12 rat pheochromocytoma was studied under the conditions of oxidative stress induced by brief incubation of the cells with hydrogen peroxide. Peptides of the general formula (Gly-Pro) n and the Pro-Gly-Pro peptide at a concentration of 0.2–100 μM were shown to decrease the number of damaged cells. The Gly-Pro peptide was the most active and decreased the number of damaged cells by 49% on average at a concentration of 100 μM. 相似文献
20.
Eva-Maria Jülke Jan-Patrick Fischer Sylvia Els-Heindl Donald Bierer Ingo Flamme Johannes Köbberling Bernd Riedl Annette G. Beck-Sickinger 《Journal of peptide science》2023,29(12):e3530
The peptide hormone adrenomedullin (ADM) consists of 52 amino acids with a disulfide bond and an amidated C-terminus. Due to the vasodilatory and cardioprotective effects, the agonistic activity of the peptide on the adrenomedullin 1 receptor (AM1R) is of high pharmacological interest. However, the wild-type peptide shows low metabolic stability leading to rapid degradation in the cardiovascular system. Previous work by our group has identified proteolytic cleavage sites and demonstrated stabilization of ADM by lipidation, cyclization, and N-methylation. Nevertheless, these ADM analogs showed reduced activity and subtype selectivity toward the closely related calcitonin gene-related peptide receptor (CGRPR). Here, we report on the rational development of ADM derivatives with increased proteolytic stability and high receptor selectivity. Stabilizing motifs, including lactamization and lipidation, were evaluated regarding AM1R and CGRPR activation. Furthermore, the central DKDK motif of the peptide was replaced by oligoethylene glycol linkers. The modified peptides were synthesized by Fmoc/t-Bu solid-phase peptide synthesis and receptor activation of AM1R and CGRPR was measured by cAMP reporter gene assay. Peptide stability was tested in human blood plasma and porcine liver homogenate and analyzed by RP-HPLC and MALDI-ToF mass spectrometry. Combination of the favorable lactam, lipidation, ethylene glycol linker, and previously described disulfide mimetic resulted in highly stabilized analogs with a plasma half-life of more than 144 h. The compounds display excellent AM1R activity and wild-type-like selectivity toward CGRPR. Additionally, dose-dependent vasodilatory effects of the ADM derivatives lasted for several hours in rodents. Thus, we successfully developed an ADM analog with long-term in vivo activity. 相似文献