Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Azirines”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMed2002

Synthesis of tag introducible (3-trifluoromethyl)phenyldiazirine based photoreactive phenylalanine.

An efficient synthesis of tag introducible (3-trifluoromethyl)phenyldiazirine based phenylalanine derivatives is described. Alkylation of a chiral glycine equivalent with a spacer containing (3-trifluoromethyl)phenyldiazirinyl bromides enables us to create photoreactive L-phenylalanine derivatives. After introduction of biotin at the spacer, the biotinylated and photoreactive amino acid was applied for L-amino acid oxidase and incorporated into a substrate binding site. These compounds will be powerful tools not only for photoaffinity labeling to elucidate properties of bioactive peptides but also as trifunctional photophors to introduce a ligand skeleton.

Azirines↗
PubMed2001

Microwave assisted solid support synthesis of novel 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazepines as potent antimicrobial agents.

An environmentally benign and economic synthesis of 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazepines is described from readily accessible substituted 2-mercapto-1-amino triazoles and substituted chalcones on basic alumina that are accelerated by exposure to microwaves. The reaction time has been brought down from hours to seconds with improved yield as compared to conventional heating. The method reported herein is devoid of the hazards of solution phase reactions. All the synthesised compounds were tested for their in vitro antibacterial and antifungal activity. Some compounds showed significant antimicrobial properties. The best activity was observed with compounds 3a, 3c, 4a and 4d.

Anti-Bacterial Agents↗
PubMed2001

Enantioselective synthesis and absolute configuration of (-)-1-(benzofuran-2-yl)-2-propylaminopentane, ((-)-BPAP), a highly potent and selective catecholaminergic activity enhancer.

Enantioselective synthesis and absolute configuration of (-)-1-(benzofuran-2-yl)-2-propylaminopentane ((-)-BPAP), which is a highly potent and selective catecholaminergic activity enhancer (CAE) substance, are described. The synthetic approach consists of the coupling reaction of benzofuran with (R)-N-tosyl-2-propylazirizine or (R)-N-methoxy-N-methylnorvaliamide, followed by appropriate modifications of the resulting coupling products. As the results, (-)-BPAP turned out to have the R configuration, which was finally confirmed by X-ray crystallographic analysis.

Azirines↗
PubMed1994

A novel biotinylated heterobifunctional cross-linking reagent bearing an aromatic diazirine.

The synthesis of a p-[(3-trifluoromethyl)diazirine-3-yl]benzoic acid derivative is described as a new carbene generating heterobifunctional cross-linking reagent. The cross-linker carries a biotin moiety in order to make use of avidin-biotin technology for specific manipulation of cross-linked components. To evaluate the ability of this reagent, the inter-subunit cross-linking of egg-white avidin tetramer was investigated. As a typical application of avidin-biotin technology for cross-linking experiments, a chemiluminescent detection method was examined to identify photobiotinylated components. A cross-linked dimeric product with an apparent molecular mass of 38 kDa was clearly visualized by the combined use of a horseradish peroxidase-streptavidin conjugate and a luminol-based chemiluminescent system.

Avidin↗
PubMed1998

A novel photoaffinity probe for the LTD4 receptor.

A novel photoaffinity probe for the leukotriene D4 receptor (LTD4) is described. L-745310, which is structurally related to the potent LTD4 antagonist MK-0476 (Singulair), was found to selectively label a 43-kDa protein in guinea-pig lung membrane previously identified as the LTD4 receptor.

Acetates↗
PubMedDate not supplied

Photolysis of 3-aryl-3-(trifluoromethyl)diazirines: a caveat regarding their use in photoaffinity probes.

The photolysis of 3-(4-tolyl)-3-(trifluoromethyl)diazirine in the presence of benzene, methanol, carbon tetrachloride, cyclohexane, triethylsilane, or diethylamine led to photoproducts consistent with the intermediacy of a singlet carbene. In the case of diethylamine, the photoinsertion into the N-H bond of diethylamine produced the expected adduct, 1-(diethylamino)-2,2,2-trifluoro-1-(4-tolyl)ethane. However, the base-catalyzed elimination of hydrogen fluoride from this adduct afforded an enamine, alpha-(diethylamino)-beta,beta-difluoro-4-methylstyrene, and the subsequent hydrolysis of this enamine furnished diethylamine and 2,2-difluoro-1-(4-tolyl)ethanone. This elimination and hydrolysis sequence effectively reversed the photoinsertion process. A similar photoinsertion and hydrolysis process using 3-(4-n-octylphenyl)-3-(trifluoromethyl)diazirine also produced 2,2-difluoro-1-(4-n-octylphenyl)ethanone in modest yield. These results suggest that the photoinsertion products from 3-aryl-3-(trifluoromethyl)-diazirines in biological systems may suffer similar fates limiting, in part, their utility in obtaining primary sequence data.

Affinity Labels↗
PubMedDate not supplied

Oriented and covalent immobilization of target molecules to solid supports: synthesis and application of a light-activatable and thiol-reactive cross-linking reagent.

Light-dependent oriented and covalent immobilization of target molecules has been achieved by combining two modification procedures: light-dependent coupling of target molecules to inert surfaces and thiol-selective reactions occurring at macromolecule or substrate surfaces. For immobilization purposes the heterobifunctional reagent N-[m-[3-(trifluoromethyl)diazirin-3-yl]phenyl]-4-maleimidobutyr amide was synthesized and chemically characterized. The photosensitivity of the carbene-generating reagent and its reactivity toward thiols were ascertained. Light-induced cross-linking properties of the reagent were documented (i) by reacting first the maleimide function with a thiolated surface, followed by carbene insertion into applied target molecules, (ii) by photochemical coupling of the reagent to an inert support followed by thermochemical reactions with thiol functions, and (iii) by thermochemical modification of target molecules prior to carbene-mediated insertion into surface materials. Procedures mentioned led to light-dependent covalent immobilization of target molecules including amino acids, a synthetic peptide, and antibody-derived F(ab') fragments. Topically selective, light-dependent immobilization was attained with the bifunctional reagent by irradiation of coated surfaces through patterned masks. Glass and polystyrene served as substrates. Molecular orientation is asserted by inherently available or selectively introduced terminal thiol functions in F(ab') fragments and synthetic polypeptides, respectively.

Amino Acid Sequence↗
PubMedDate not supplied

Hexestrol diazirine photoaffinity labeling reagent for the estrogen receptor.

3-Azibutyl (2R*,3S*)-2,3-bis(4-hydroxyphenyl)pentyl sulfide (1), a photoaffinity labeling reagent for the estrogen receptor (ER), has been prepared in unlabeled and in high specific activity tritium-labeled form (32 Ci/mmol) and has been shown to undergo selective and efficient photocovalent attachment to rat uterine ER. Diazirine 1 demonstrates high binding affinity for ER, as determined by both a competitive binding assay and a direct binding assay (relative binding: estradiol = 100; (1) = 17. Kd: estradiol = 0.19 nM; (1) = 0.98 nM, respectively). It is efficient in site-specific photoinactivation of ER, reaching the level of 31% after 5 min of irradiation at > 315 nm. The tritium-labeled diazirine [3H]-1 undergoes specific photocovalent attachment to ER with an attachment efficiency of 29% and a selectivity of 90%. Both of these values are quite high for a photoaffinity reagent. SDS-polyacrylamide gel electrophoretic analysis of the photolabeled proteins shows specific labeling of a major species at M(r) 65,000, the same species that is labeled by [3H]tamoxifen aziridine, a well-characterized affinity label for ER. Hexestrol diazirine 1 is the first carbene-generating photoaffinity label that covalently labels ER with high efficiency and selectivity, and it should be useful in further studies on the hormone-binding domain of ER.

Affinity Labels↗
PubMedDate not supplied

Photoimmobilization of a bioactive laminin fragment and pattern-guided selective neuronal cell attachment.

To attain light-dependent functionalization of biocompatible materials, a photolabel-derivatized, bioactive laminin fragment has been synthesized, chemically characterized, and photoimmobilized. Covalent high-resolution patterning of the laminin fragment CDPGYIGSR to hydroxylated fluorinated ethylene propylene (FEP-OH), poly(vinyl alcohol), and glycophase glass has been achieved. The synthetic peptide CDPGYIGSR was thermochemically coupled to either N-[m-[3-(trifluoromethyl)-diazirin-3-yl]phenyl]-4-maleimidobuty ramide or 4-maleimidobenzophenone. Photolabel-derivatized peptides were radiolabeled, and 20 and 300 microns-sized patterns were visualized by autoradiography. The biospecific interaction of photoimmobilized laminin fragments with cells was investigated by analyzing the selective attachment of NG 108-15 neuroblastoma x glioma cells which bear CDPGYIGSR-specific cell surface receptors. On photopatterned FEP-OH membranes NG 108-15 cells differentiated in serum-supplemented media within 1 day. Specific attachment to the immobilized oligopeptide CDPGYIGSR was assessed in serum-free media with competitive binding studies, showing an 82% decrease in cell adherence after the cell receptors were blocked with soluble CDPGYIGSR.

Amino Acid Sequence↗
PubMed2000

Interaction of lipid-bound myelin basic protein with actin filaments and calmodulin.

Myelin basic protein (MBP) binds to negatively charged lipids on the cytosolic surface of oligodendrocytes (OLs) and is believed to be responsible for adhesion of these surfaces in the multilayered myelin sheath. MBP in solution has been shown by others to bind to both G- and F-actin, to bundle F-actin filaments, and to induce polymerization of G-actin. Here we show that MBP bound to acidic lipids can also bind to both G- and F-actin and cause their sedimentation together with MBP-lipid vesicles. Thus it can simultaneously utilize some of its basic residues to bind to the lipid bilayer and some to bind to actin. The amount of actin bound to the MBP-lipid vesicles decreased with increasing net negative surface charge of the lipid vesicles. It was also less for vesicles containing the lipid composition predicted for the cytosolic surface of myelin than for PC vesicles containing a similar amount of an acidic lipid. Calmodulin caused dissociation of actin from MBP and of the MBP-actin complex from the vesicles. However, it did not cause dissociation of bundles of actin filaments once these had formed as long as some MBP was still present. These results suggest that MBP could be a membrane actin-binding protein in OLs/myelin and its actin binding can be regulated by calmodulin and by the lipid composition of the membrane. Actin binding to MBP decreased the labeling of MBP by the hydrophobic photolabel 3-(trifluoromethyl)-3-(m-[(125)I]iodophenyl)diazirine (TID), indicating that it decreased the hydrophobic interactions of MBP with the bilayer. This change in interaction of MBP with the bilayer could then create a cytosol to membrane signal caused by changes in interaction of the cytoskeleton with the membrane.

Actins↗
PubMed1992

Mapping the lipid-exposed regions in the Torpedo californica nicotinic acetylcholine receptor.

To identify regions of the Torpedo nicotinic acetylcholine receptor (AchR) interacting with membrane lipid, we have used 1-azidopyrene (1-AP) as a fluorescent, photoactivatable hydrophobic probe. For AchR-rich membranes equilibrated with 1-AP, irradiation at 365 nm resulted in covalent incorporation in all four AchR subunits with each of the subunits incorporating approximately equal amounts of label. To identify the regions of the AchR subunits that incorporated 1-AP, subunits were digested with Staphylococcus aureus V8 protease and trypsin, and the resulting fragments were separated by SDS-PAGE followed by reverse-phase high-performance liquid chromatography. N-terminal sequence analysis identified the hydrophobic segments M1, M3, and M4 within each subunit as containing the sites of labeling. The labeling pattern of 1-AP in the alpha-subunit was compared with that of another hydrophobic photoactivatable probe, 3-trifluoromethyl-3-(m-[125I]iodophenyl)diazirine ([125I]TID). The nonspecific component of [125I]TID labeling [White, B., Howard, S., Cohen, S. G., & Cohen, J.B. (1991) J. Biol. Chem. 266, 21595-21607] was restricted to the same regions as those labeled by 1-AP. The [125I]TID residues labeled in the hydrophobic segment M4 were identified as Cys-412, Met-415, Cys-418, Thr-422, and Val-425. The periodicity and distribution of labeled residues establish that the M4 region is alpha-helical in nature and indicate that M4 presents a broad face to membrane lipid.

Amino Acid Sequence↗
PubMed2000

Identifying the lipid-protein interface and transmembrane structural transitions of the Torpedo Na,K-ATPase using hydrophobic photoreactive probes.

To identify regions of the Torpedo Na,K-ATPase alpha-subunit that interact with membrane lipid and to characterize conformationally dependent structural changes in the transmembrane domain, we have proteolytically mapped the sites of photoincorporation of the hydrophobic compounds 3-(trifluoromethyl)-3-(m-[(125)I]iodophenyl)diazirine ([(125)I]TID) and the phosphatidylcholine analogue [(125)I]TIDPC/16. The principal sites of [(125)I]TIDPC/16 labeling were identified by amino-terminal sequence analysis of proteolytic fragments of the Na,K-ATPase alpha-subunit and are localized to hydrophobic segments M1, M3, M9, and M10. These membrane-spanning segments have the greatest levels of exposure to the lipid bilayer and constitute the bulk of the lipid-protein interface of the Na,K-ATPase alpha-subunit. The extent of [(125)I]TID and [(125)I]TIDPC/16 photoincorporation into these transmembrane segments was the same in the E(1) and E(2) conformations, indicating that lipid-exposed segments located at the periphery of the transmembrane complex do not undergo large-scale movements during the cation transport cycle. In contrast, for [(125)I]TID but not for [(125)I]TIDPC/16, there was enhanced photoincorporation in the E(2) conformation, and this component of labeling mapped to transmembrane segments M5 and M6. Conformationally sensitive [(125)I]TID photoincorporation into the M5 and M6 segments does not reflect a change in the levels of exposure of these segments to the lipid bilayer as evidenced by the lack of [(125)I]TIDPC/16 labeling of these two segments in either conformation. These results suggest that [(125)I]TID promises to be a useful tool for structural characterization of the cation translocation pathway and for conformationally dependent changes in the pathway. A model of the spatial organization of the transmembrane segments of the Na,K-ATPase alpha- and beta-subunits is presented.

Animals↗