固定化金属离子亲和发光二氧化硅纳米粒子的制备及其用于磷酸化蛋白免疫印迹标记

发展了一种能够识别磷酸化蛋白的固定化金属离子亲和发光二氧化硅纳米粒子用于免疫印迹(Western Blot)磷酸化蛋白的标记.首先通过反相微乳液St?ber方法合成了掺杂异硫氰酸荧光素硅烷化衍生物的发光二氧化硅(FITC@SiO2)球形纳米粒子,粒子平均粒径为60 nm.然后通过共聚反应在FITC@SiO2纳米粒子表面...     

Chemical proteomics reveals ligustilide targets SMAD3, inhibiting collagen synthesis in aortic endothelial cells

Atherosclerosis is a persistent inflammatory state,while vascular endothelial fibrosis is one of the primary causes of atherosclerosis development.Although ligustilide(Lig) was shown to exert obvious antiatherogenic effects in previous studies,its precise mechanism has not been deeply discussed.In this paper,we designed a Lig-derived photoaffinity labelling(PAL) probe to identify potential therapeutic targets of Lig via chemical proteomics approach.Mothers against decapentaplegic homologue 3(SMAD3),a signal transmitter of transforming growth factor-β(TGF-β) which promotes the development of vascular fibrosis,was identified as a potential target of Lig.Lig suppressed the phosphorylation and nuclear translocation of SMAD3 by blocking the interaction between SMAD3 and TGF-β receptor 1,thereby inhibiting the collagen synthesis process.Hence,developing a novel SMAD3 inhibitor may present a promising therapeutic option for preventing vascular fibrosis.     

2‐Substituted dATP Derivatives as Building Blocks for Polymerase‐Catalyzed Synthesis of DNA Modified in the Minor Groove

2′‐Deoxyadenosine triphosphate (dATP) derivatives bearing diverse substituents (Cl, NH₂, CH₃, vinyl, ethynyl, and phenyl) at position 2 were prepared and tested as substrates for DNA polymerases. The 2‐phenyl‐dATP was not a substrate for DNA polymerases, but the dATPs bearing smaller substituents were good substrates in primer‐extension experiments, producing DNA substituted in the minor groove. The vinyl‐modified DNA was applied in thiol–ene addition and the ethynyl‐modified DNA was applied in a CuAAC click reaction to form DNA labelled with fluorescent dyes in the minor groove     

Pristinol,a Sesquiterpene Alcohol with an Unusual Skeleton from Streptomyces pristinaespiralis

A terpene cyclase from Streptomyces pristinaespiralis was characterized as the synthase for (+)‐(2S,3S,9R)‐pristinol. The structure of this sesquiterpene alcohol, which has a new carbon skeleton, was established by NMR spectroscopy and single‐wavelength anomalous‐dispersion X‐ray crystallography. Extensive isotopic labelling experiments were performed to distinguish between various possible cyclization mechanisms of the terpene cyclase and to decipher the EI‐MS fragmentation mechanism for pristinol.     

Raman spectroscopy of n‐pentyl methyl ether and deuterium labelled analogues

The Raman spectra of n‐pentyl methyl ether, C₅H₁₁OCH₃, and six selectively deuteriated analogues are reported and discussed. Correlations between the observed ν(sp³CH) stretching and bending bands and the position of the deuterium atoms in the alkyl chain are developed and refined. Similar progress is possible in associating specific skeletal vibrations with bands in the Raman spectra. The relevance of this study to improving the assignment of bands in the Raman spectra of larger systems of biological interest is highlighted. Copyright © 2010 John Wiley & Sons, Ltd.     

Human Serum Albumin Labelling with a New BODIPY Dye Having a Large Stokes Shift

BODIPY dyes are photostable neutral derivatives of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene. These are widely used as chemosensors, laser materials, and molecular probes. At the same time, BODIPY dyes have small or moderate Stokes shifts like most other fluorophores. Large Stokes shifts are preferred for fluorophores because of higher sensitivity of such probes and sensors. The new boron containing BODIPY dye was designed and synthesized. We succeeded to perform an annulation of pyrrole ring with coumarin heterocyclic system and achieved a remarkable difference in absorption and emission maximum of obtained fluorophore up to 100 nm. This BODIPY dye was equipped with linker arm and was functionalized with a maleimide residue specifically reactive towards thiol groups of proteins. BODIPY residue equipped with a suitable targeting protein core can be used as a suitable imaging probe and agent for Boron Neutron Capture Therapy (BNCT). As the most abundant protein with a variety of physiological functions, human serum albumin (HSA) has been used extensively for the delivery and improvement of therapeutic molecules. Thiolactone chemistry provides a powerful tool to prepare albumin-based multimodal constructions. The released sulfhydryl groups of the homocysteine functional handle in thiolactone modified HSA were labeled with BODIPY dye to prepare a labeled albumin-BODIPY dye conjugate confirmed by MALDI-TOF-MS, UV-vis, and fluorescent emission spectra. Cytotoxicity of the resulting conjugate was investigated. This study is the basis for a novel BODIPY dye-albumin theranostic for BNCT. The results provide further impetus to develop derivatives of HSA for delivery of boron to cancer cells.     

Elucidation of the Structure of Lignin–Carbohydrate Complexes in Ginkgo CW-DHP by 13C-2H Dual Isotope Tracer

To elucidate the chemical linkages between lignin and carbohydrates in ginkgo cell walls, ¹³C-²H-enriched cell wall-dehydrogenation polymers (CW-DHP) were selectively prepared with cambial tissue from Ginkgo biloba L. by feeding D-glucose-[6-²H₂], coniferin-[α-¹³C], and phenylalanine ammonia-lyase (PAL) inhibitor. The abundant detection of ¹³C and ²H confirmed that D-glucose-[6-²H₂] and coniferin-[α-¹³C] were involved in the normal metabolism of ginkgo cambial cells that had been effectively labelled with dual isotopes. In the ginkgo CW-DHP, ketal and ether linkages were formed between the C-α of lignin side chains and carbohydrates, as revealed by solid state CP/MAS ¹³C-NMR differential spectroscopy. Furthermore, the DMSO/TBAH ionic liquids system was used to fractionate the ball-milled CW-DHP into three lignin-carbohydrate complex (LCC) fractions: glucan–lignin complex (GL), glucomannan–lignin complex (GML), and xylan–lignin complex (XL). The XRD determination indicated that the cellulose type I of the GL was converted into cellulose type II during the separation process. The molecular weight was in the order of Ac-GL > Ac-GML > XL. The ¹³C-NMR and ¹H-NMR differential spectroscopy of ¹³C-²H-enriched GL fraction indicated that lignin was linked with cellulose C-6 by benzyl ether linkages. It was also found that there were benzyl ether linkages between the lignin side chain C-α and glucomannan C-6 in the ¹³C-²H-enriched GML fraction. The formation of ketal linkages between the C-α of lignin and xylan was confirmed in the ¹³C-²H-enriched XL fraction.     

Eco-friendly synthesis of 2-aryl-1-arylmethyl-1H-benzimidazoles using alumina-sulfuric acid as a heterogeneous reusable catalyst

A cost-effective and eco-friendly synthesis of 2-aryl-1-arylmethyl-1H-benzimidazoles has been developed through the condensation of different aldehydes with o-phenylenediamine using alumina-sulfuric acid as a recyclable heterogeneous solid acid catalyst. Morphological properties of the catalyst have been investigated. Effect of different solvents and comparison of alumina-sulfuric acid with different acid catalysts have also been studied. A plausible mechanistic pathway has been proposed on the basis of the isotope labelling experiments where catalytic behaviour of alumina-sulfuric acid has been explained.     

Novel formal synthesis of stereospecifically C-6 deuterated d-glucose employing configurationally stable alkoxymethyllithiums

The synthesis and testing of configurational stability of chirally monodeuterated PMB- and THP-substituted oxymethyllithiums are described. Macroscopically they are configurationally stable up to −35 °C, the limit of their chemical stability, and microscopically even up to 0 °C. Furthermore, THP-protected oxy-[D₁]methyllithium has been applied in the formal synthesis of (6R)-[6-D₁]-d-glucose (four steps, 40% yield), an example of its use as a homochiral hydroxymethyl synthon.     

Syntheses of High‐Valent fac‐[99mTcO3]+ Complexes and [3+2] Cycloadditions with Alkenes in Water as a Direct Labelling Strategy

Reported herein is a new concept for the labelling of biomolecules with small [^{99 m}TcO₃]⁺ complexes through a [3+2] cycloaddition with alkenes for radiopharmaceutical applications. We developed convenient reactions for the synthesis of small, water stable fac‐[TcO₃(tacn‐R)]⁺ complexes (⁹⁹Tc and ^99mTc, tacn=1,4,7‐triazacyclononane, R=H, ‐CH₂‐C₆H₅, ‐CH₂‐C₆H₄COOH). With alkenes, these high valent [^99mTcO₃]⁺ complexes undergo [3+2] cycloaddition with formation of the corresponding Tc^V–glycolato complexes. The ^99mTc^V and ^99mTc^VII complexes are stable at 37 °C in water and in the presence of serum proteins. Therefore, new opportunities in technetium chemistry are enabled with a high potential for medicinal and biological applications. In contrast to classical labelling, the presented strategy is ligand and not metal‐centred.