Unique electrospun fiber properties obtained by blending elastin-like peptides and highly-ionized peptides

The hypothesis that novel material properties can be realized by blending polypeptides of starkly different amino acid composition has been tested. The polymer feedstock consisted of a novel recombinant elastin-like peptide (ELP) or a mixture of an ELP and a synthetic polypeptide, co-poly(l-glutamic acid₄, l-tyrosine₁) (PLEY), dissolved in water. Suitability of the polymers for materials fabrication has been assayed by electrospinning. Polymer structure in cast films and electrospun fibers by infrared (IR) spectroscopy. Scanning electron microscopy (SEM) analysis has revealed unique morphological properties of fibers spun from polymer blends of ELP and PLEY, properties not displayed by either polymer alone. Fluorescence microscopy showed that little if any phase separation occurred in the blended fibers. The materials of this research may present advantages for electrospun fiber applications in drug delivery and other areas. More generally, the present results will advance the growing field of peptide-based materials.     

Secondary structures of peptides

Summary 75.46 MHz ¹³C-NMR CP/MAS spectra of solid poly(1-alanines) with various degrees of polymerization were measured. The signals of all three carbons are split into two peaks. One peak presents the -helix structure and one the pleated sheet form. Equimolar mixtures of helical poly(L-alanine) with poly(glycine) and poly(L-valine) were measured under various conditions. It was found that the peak areas are proportional to the mole ratios of the different secondary structures and neither a mismatch of the Hartmann-Hahn conditions nor variations of the mixing time or the pulse interval (relaxation delay) have a significant influence on the intensity ratios. Hence, a quantitative evaluation of the ¹³C NMR spectra with respect to the secondary structure is feasible.Herrn Prof. Dr. H. Zahn zum 65. Geburtstag gewidmet     

Chemical and enzymatic synthesis of fluorinated-dehydroalanine-containing peptides

Michael acceptors have long been recognized as reactive functionalities that may link a biologically active molecule to its cellular target. 1,2-Dehydro amino acids are potential Michael acceptors present in a large number of natural products, but their reactivity is modulated by the deactivating nature of the alpha-amino group engaged in an amide bond. We describe here the preparation of 3-fluoro-1,2-dehydroalanine moieties within peptides that significantly enhance the reactivity of the Michael acceptor. Two different routes were designed to access these compounds, one relying on chemical means to introduce the desired functionality and the second taking advantage of a peptide epimerase. In the chemical approach, the fluoro-Pummerer reaction of cysteine derivatives afforded 3-fluorocysteine residues that were oxidized to the corresponding sulfoxides, followed by thermolytic elimination to provide the desired 3-fluorodehydroalanines. The mechanism of the fluoro-Pummerer reaction was investigated and several possible pathways were ruled out. The enzymatic approach utilized the dipeptide epimerase YcjG from Escherichia coli. Difluorinated alanine was incorporated at the C terminus of a dipeptide by chemical means. The resulting peptide proved to be a substrate for YcjG, which catalyzed fluoride elimination to provide the 3-fluorodehydroalanine-containing peptide. Mechanistic investigations showed that fluoride elimination occurred faster than epimerization and at a rate close to that of epimerization of Ala-Ala.     

胜肽在化妆品中的应用和最新进展

介绍了美容胜肽的定义及其在化妆品中的发展概况。总结了国内外化妆品成品品牌使用美容胜肽的情况。按照功能机理对美容胜肽进行分类和介绍。同时展望了胜肽美容化妆品的未来发展趋势,为中国胜肽化妆品产品的发展提供参考。     

绿豆肽对RAW264.7巨噬细胞的免疫调节作用

目的探讨绿豆肽对RAW264. 7巨噬细胞的免疫调节作用。方法在体外培养的RAW264. 7巨噬细胞中,分别加入10、100、200和400μg/mL的绿豆肽,检测RAW264. 7巨噬细胞的增殖能力、吞噬能力、SOD酶活力、NO含量和细胞因子分泌量,同时检测绿豆肽对经脂多糖(lipo-polysaccharide,LPS)诱导的RAW264. 7巨噬细胞中细胞因子分泌和LC3、p62蛋白表达水平的影响。结果与空白对照组比较,不同浓度绿豆肽组RAW264. 7巨噬细胞的增殖率及吞噬率显著提高(P 0. 05),400和200μg/mL组的SOD酶活力、NO含量及分泌TNF-α、IL-1β、IL-6水平均显著升高(P 0. 05)。各浓度绿豆肽均可显著抑制LPS诱导RAW264. 7巨噬细胞的TNF-α、IL-1β和IL-6分泌量(P 0. 05),浓度为400μg/mL时,上述细胞因子的分泌量与空白对照组差异无统计学意义(P 0. 05)。不同浓度绿豆肽均可降低LPS诱导RAW264. 7巨噬细胞胞内LC3的含量,上调p62蛋白的表达量。结论绿豆肽可激活巨噬细胞、增加自身代谢酶活力、释放细胞因子,通过抗炎作用及抑制细胞自噬,从而提高宿主细胞的免疫功能。     

Nanomaterials based on peptides

Owing to the assortment of functional groups, peptides are capable of self-assembly and formation of regularly patterned supramolecular complexes. Peptide-based nanomaterials offer promise for medicine, engineering, and bioimaging. The present review surveys the structure and characteristics of filaments formed by peptides of various secondary structures and their further assembly into 2D and 3D nanomaterials. Possible application areas of self-assembling peptide systems, including the synthesis of inorganic nanomaterials, are considered.     

Photoresponsive dendritic azobenzene peptides

Two dendritic peptides containing a branched lysine core and up to eight azobenzene moieties in the periphery were synthesized on solid support employing the omega-amino acid 4-(aminomethyl)phenylazobenzoic acid. With an additional peptidic tail consisting of an oligolysine portion, water solubility was achieved for the dendrimers, which allowed for the characterization of the cis/trans photoisomerization of the dendritic azobenzene species in both organic and aqueous media. Despite the interactions between the chromophores, which occur particularly in aqueous media, at higher dilution the photoisomerization process was found to proceed to extents that should permit photomodulation of molecular recognition processes between ligands grafted to the photosensitive azobenzene units and receptor molecules.     

阿片肽链中L-苯丙氨酸的保护全合成及表征

L-苯丙氨酸经硝化、酯化、叔丁氧羰基(Boc)保护α-氨基、Pd/C还原对位硝基、对甲磺酰氯(MSC1)保护对位氨基、经水解反应后,在酸性条件下脱去叔丁氧羰基(Boc)基团,碱性条件下引入9-芴甲氧羰酰琥珀酰亚胺(Fmocosu),最终生成标题化合物,并且对所合成标题化合物进行了HNMR结构确证。     

家蝇抗菌肽抑菌活性及其稳定性研究

通过体外抑菌实验,采用纸片扩散法对家蝇抗菌肽的抑菌性进行定性研究。试验用菌有金黄色葡萄球菌、大肠杆菌、绿脓杆菌、白色念珠菌和黑曲霉菌。在对家蝇抗菌肽抗菌谱研究的基础上,进一步用肉汤稀释法（试管法）定量测定其最低抑菌浓度（MIC）,并对其稳定性进行研究。结果表明,家蝇抗菌肽对金黄色葡萄球菌、绿脓杆菌和大肠杆菌3种细菌有较好的抑制作用,而对白色念珠菌和黑曲霉没有明显的抑制作用,对金黄色葡萄球菌、绿脓杆菌和大肠杆菌最低抑菌浓度（MIC）分别为0.156 mg/mL、0.312 5 mg/mL和6.25 mg/mL。另外,对其稳定性进行讨论,结果表明,家蝇抗菌肽的稳定性良好。