游离胆红素与固体碳酸钙的相互作用

应用红外光谱的方法研究了溶液中游离胆红素与固体碳酸钙的相互作用,探讨了色素型胆结石的形成机理.研究结果表明,溶液中游离的胆红素可以与固体碳酸钙作用,游离胆红素通过与固体碳酸钙表面的钙作用生成难溶性的胆红素钙络合物.牛磺胆酸钠、胆酸钠和脱氧胆酸钠的加入能阻止游离胆红素与碳酸钙的作用,其中加入牛磺胆酸钠后,游离胆红素几乎不与碳酸钙作用.     

Progress in the study on the composition and formation mechanism of gallstone

Our serial studies from 1970s on chemical composition, structure determination and formation mechanism of gallstones were reviewed. The chemical component investigation of brown-pigment gallstone demonstrated that it consists of macromolecules such as proteins, glyco-proteins, polysaccharides, bilirubin polymers and pigment polymers, and biomolecules such as cholesterol, bile salts, calcium salts of carbonate, phosphate, fatty acids and bilirubinate as well as various metal ions. The binding of metal ions with bile salts and bilirubin plays important roles in gallstone formation, i.e., calcium bilirubinate complex is the major constitute of brown-pigment gallstones, and copper bilirubinate complex is critical in the black color appearance of black-pigment gallstone. The cross section of many gallstones exhibits a concentric ring structure composed of various small particles with a fractal character. This is nonlinear phenomenon in gallstone formation. A typical model system of metal ions-deoxycholate (or cho     

Native conformation at specific residues in recombinant inclusion body protein in whole cells determined with solid-state NMR spectroscopy

Inclusion bodies are insoluble aggregates that are formed by bacteria to store excess recombinant protein produced during expression. The structure of the protein in inclusion bodies is poorly understood but it has been hypothesized that the protein may form misfolded beta sheet aggregates. This paper presents an isotopic labeling and solid-state nuclear magnetic resonance approach to determine the secondary structure of individual residues within a recombinant influenza virus "FHA2" protein in inclusion bodies. The inclusion bodies were studied either in the context of the unlysed hydrated E. coli cells or in the hydrated pellet formed from centrifugation of the material insoluble in the cell lysate. The native structure of FHA2 is predominantly helical and native helical structure was also observed for several specific residues in the inclusion body FHA2. This approach will be applicable to structural analysis of many inclusion body proteins and should provide useful information for optimizing solubilization and purification protocols of these proteins.     

胆色素结石的结构和难溶组分的分析

本实验采用一系列不同的溶剂对溶解前后的胆色素类结石进行了红外光谱观测，并分别用Ｘ射线能谱仪和元素分析仪对无机和有机元素进行检测和分析。通过比较溶解前后的红外光谱、无机和有机元素含量的变化，讨论了胆红素与金属离子的结合方式、色素类结石难溶的原因以及可能的成石机制。     

色素类胆结石难溶原因的分析

本文采用不同的溶剂对溶解前后的胆色素类结石进行了主要元素的控制，同时对特征色素类结石进行了有机元素分析，通过比较溶解前后超微结构和各种元素含量的变化，认为胆红素与金属离子，尤其是钙及其后二阶金属离子，形成了胆色素盐或配位络合物，并与糖蛋白等螯合成了大分子复合物。这是胆色素类结石难溶的主要原因。     

Evaluation of gallbladder emptying in patients with chronic liver disease by 99mTc-EHIDA hepatobiliary scintigraphy

Gallbladder emptying after intramuscular injection of cerulein was investigated by 99mTc-EHIDA hepatobiliary scintigraphy in 23 patients with biliary disease, 55 patients with chronic liver disease, and 21 normal controls. The mean gallbladder ejection fraction in patients with gallstones and liver cirrhosis was significantly reduced compared with normal controls. (gallstones: 56.3 +/- 21.3%, LC with gallstones: 50.8 +/- 29.6%, LC without gallstones: 55.9 +/- 26.7%, vs. normal controls: 74.4 +/- 12.9%, p less than 0.01). The mechanism for sluggish gallbladder emptying in liver cirrhosis is unknown, however impaired emptying with bile stasis provides a potential pathophysiologic basis for the high frequency of pigment stones.     

Surface tailoring for controlled protein adsorption: effect of topography at the nanometer scale and chemistry

Protein adsorption behavior is at the heart of many of today's research fields including biotechnology and materials science. With understanding of protein-surface interactions, control over the conformation and orientation of immobilized species may ultimately allow tailor-made surfaces to be generated. In this contribution protein-surface interactions have been examined with particular focus on surface curvature with and without surface chemistry effects. Silica spheres with diameters in the range 15-165 nm with both hydrophilic and hydrophobic surface chemistries have been used as model substrates. Two proteins differing in size and shape, bovine serum albumin (BSA) and bovine fibrinogen (Fg), have been used in model studies of protein binding with detailed secondary structure analysis being performed using infrared spectroscopy (IR) on surface-bound proteins. Although trends in binding affinity and saturation values were similar for both proteins, albumin is increasingly less ordered on larger substrates, while fibrinogen, in contrast, loses secondary structure to a greater extent when adsorbing onto particles with high surface curvature. These effects are compounded by surface chemistry, with both proteins becoming more denatured on hydrophobic surfaces. Both surface chemistry and topography play key roles in determining the structure of the bound proteins. A model of the binding characteristics of these two proteins onto surfaces having differing curvature and chemistry is presented. We propose that properties of an adsorbed protein layer may be guided through careful consideration of surface structure, allowing the fabrication of materials/surface coatings with tailored bioactivity.     

Synthetic melanin is a model for soluble natural eumelanin in UVA-photosensitised superoxide production

Studies to UV-irradiate natural eumelanins in vitro have used insoluble pigment obtained by acid hydrolysis, which lacks melanoprotein. Eumelanin synthesised in the presence of a protein is not insoluble, and the insoluble form of melanin from acid hydrolysis may not have the same physicochemical properties as the natural pigment synthesised in vivo in the melanosome. Here we investigated radical production by three natural eumelanins exposed to solar levels of UVA; sepia melanin from Sepia officinalis, and eumelanins isolated from Oriental human and domestic cat hair. UVA irradiation of sepia melanin in solution at pH 4.5 in the presence of the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) gave hydroperoxyl and hydroxyl radical-adducts, maximal at 0.6-2.5 mg/ml melanin concentrations. Hydroperoxyl radical production was relatively low in acetate buffer, but detected in aqueous suspensions of sepia melanin. Hair eumelanins were photoreactive with hydroperoxyl radical-adduct production at low concentrations (0.1-0.4 mg/ml melanin). Synthetic pigment after synthesis undergoes photo-oxidation (producing superoxide) at low concentrations (0.3 mg/ml) and its oxidation increases the photoreactivity at higher melanin concentrations. These findings may be physiologically relevant to the properties and function of eumelanin in vivo when it is at low concentration (found in a small proportion of Caucasian melanocytes), and suggest that synthetic melanin has the potential for the basis of a model for natural eumelanin.     

Black Pigment Gallstone Inspired Platinum‐Chelated Bilirubin Nanoparticles for Combined Photoacoustic Imaging and Photothermal Therapy of Cancers

Bilirubin (BR), a bile pigment that exerts potent antioxidant and anti‐inflammatory effects, is also a major constituent of black pigment gallstones found in bile ducts under certain pathological conditions. Inspired by the intrinsic metal‐chelating power of BR found in gallstones, herein we report a cisplatin‐chelated BR‐based nanoparticle (cisPt@BRNP) for use as a new photonic nanomedicine for combined photoacoustic imaging and photothermal therapy of cancers. The cisPt@BRNPs were prepared by simply mixing cisplatin with BRNPs, yielding ca. 150‐nm‐size NPs. Upon near‐IR laser irradiation at 808 nm, cisPt@BRNPs generated considerable heat and induced clear death of cancer cells in vitro. Following intravenous injection into human colon cancer‐bearing mice, cisPt@BRNPs allowed effective tumor visualization by photoacoustic imaging and remarkable antitumor efficacy by photothermal therapy, suggesting their potential for use as a new photonic nanomedicine for cancer therapy.     

Molecular mechanisms of polypeptide aggregation in human diseases

Protein aggregation is implicated in a plethora of neurodegenerative diseases. The proteins found to aggregate in these diseases are unrelated in their native structures and amino acid sequences, but form similar insoluble fibrils with characteristic cross-beta sheet morphologies called amyloid in the aggregated state. While both the mechanism of aggregation and the structure of the aggregates are not fully understood at the molecular level, recent studies provide strong support for the idea that protein aggregation into highly stable, insoluble amyloid structures is a general property of the polypeptide chain. For proteins with a unique native state, it is known that aggregation occurs under conditions that promote native-state destabilization in vitro and in vivo. Taken together, the results of several important recent investigations suggest three broad molecular frameworks that may underlie the conversion of normally soluble peptides and proteins into insoluble amyloid fibrils: (1) edge-strand hydrogen bonding, (2) domain-swapping, and (3) self-association of amyloidogenic fragments. We argue that these underlying scenarios are not mutually exclusive and may be protein-dependent - i.e., a protein with a high content of hinge-regions may aggregate via a runaway domain-swap, whereas a protein with a high content of amyloidogenic fragments may aggregate primarily by the self-association of these fragments. These different scenarios provide frameworks to understand the molecular mechanism of polypeptide aggregation.     

Regulation of silica morphology by proteins serving as a template for mineralization

The fabrication of inorganic materials under the control of biopolymers is a research field of tremendous interest because in diatoms and sponges the specific proteins direct the formation of silica at ambient conditions that have highly organized structure at multiple length scales and properties that the material scientists can only aspire to achieve. Here it is demonstrated by using a novel biocompatible precursor that common proteins - albumin, caseins and gelatin - can mediate formation of hybrid nanocomposite materials through catalyzing the sol-gel processes and templating silica generated in situ. Serving as the template, the proteins provide a unique opportunity to regulate the silica morphology and properties by means of a change of their secondary and tertiary structure through pH and temperature.     

Effects of surface curvature and surface chemistry on the structure and activity of proteins adsorbed in nanopores

The interactions of proteins with the surface of cylindrical nanopores are systematically investigated to elucidate how surface curvature and surface chemistry affect the conformation and activity of confined proteins in an aqueous, buffered environment. Two globular proteins, lysozyme and myoglobin, with different catalytic functions, were used as model proteins to analyze structural changes in proteins after adsorption on ordered mesoporous silica SBA-15 and propyl-functionalized SBA-15 (C(3)SBA-15) with carefully controlled pore size. Liquid phase ATR-FTIR spectroscopy was used to study the amide I and II bands of the adsorbed proteins. The amide I bands showed that the secondary structures of free and adsorbed protein molecules differ, and that the secondary structure of the adsorbed protein is influenced by the local geometry as well as by the surface chemistry of the nanopores. The conformation of the adsorbed proteins inside the nanopores of SBA-15 and C(3)SBA-15 is strongly correlated with the local geometry and the surface properties of the nanoporous materials, which results in different catalytic activities. Adsorption by electrostatic interaction of proteins in nanopores of an optimal size provides a favorably confining and protecting environment, which may lead to considerably enhanced structural stability and catalytic activity.     

Protein‐like structure and activity in synthetic polymers

The structure and activity of proteins is the gold standard for functional polymeric materials. This highlight seeks to calibrate the reader with respect to recent attempts to mimic the various structural and functional traits of proteins using the techniques of modern polymer chemistry. From advances in sequence‐controlled polymers (primary structure), to peptidomimetics, foldamers, single‐chain nanoparticles (secondary and tertiary structure), accessing the various structural aspects of protein chemistry is a vibrant research area. Likewise, the properties and utility of proteins in applications such as catalysis and molecular recognition are being emulated in the laboratory to great effect. Rather than provide an exhaustive review on any one of these topics, this article seeks to highlight the common thread among them, encouraging discussion and collaboration that will result in the next generation of smart materials with advanced structure and function. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 191–206     

Highly ordered structures of peptides by using molecular scaffolds

Protein secondary structures such as alpha-helices, beta-sheets, and beta-turns are important in inducing the three-dimensional structure and biological activity of proteins. Designing secondary structure mimics composed of short peptides has attracted much attention not only to gain fundamental insight into the factors affecting protein folding but also to develop pharmacologically useful compounds, artificial receptors, asymmetric catalysts, and new materials. In this tutorial review, we focus on molecular scaffolds employed to induce beta-sheet-like structure in attached peptide chains, thereby creating highly ordered molecular structures, and discuss the versatility of these molecular scaffolds to regulate the attached peptide strands in the appropriate dimensions.     

红外和拉曼光谱用于对丝蛋白构象的研究

动物丝纤维和相关丝蛋白材料的性能与丝蛋白本身的二级结构即构象密切相关。红外光谱和拉曼光谱是研究蛋白质构象的有力手段，因此在丝蛋白结构的研究中也有广泛的应用。本文综述了红外光谱和拉曼光谱在家蚕、野蚕(主要是柞蚕)和蜘蛛丝蛋白研究方面的应用，并对表征丝蛋白各种构象的红外和拉曼特征峰进行了较为全面的归纳总结。     

Facile fabrication of colored superhydrophobic coatings by spraying a pigment nanoparticle suspension

Superhydrophobic coatings were prepared by spraying a pigment nanoparticle suspension. By changing the type of pigment nanoparticles, the colors of the coating could be controlled. The particle size of the pigments, which determines the surface structure of the coatings, played an important role in exhibiting superhydrophobicity. The spray-coating process is applicable to a variety of materials (e.g., copper, glass, paper, coiled wire, and tied thread), and the superhydrophobicity was repairable.     

Proteomic analysis of chicken eggshell cuticle membrane layer

The eggshell is a barrier that plays an important role in the defense of the egg against microbial and other infections; it protects the developing bird against unfavorable impacts of the environment and is essential for the reproduction of birds. The avian eggshell is a complex structure that is formed during movement along the oviduct by producing a multilayered mineral-organic composite. The extractable proteins of avian eggshells have been studied extensively and many of them identified, however, the insoluble (non-extractable) proteins have been sparsely studied. We studied the EDTA-insoluble proteinaceous film from the cuticle layer of eggshell. This film consists of three main areas: spots (cca 300 μm diameter), blotches (small spots with diameter only tens of μm), and the surroundings (i.e., the area without spots and blotches) where spots contain a visible accumulation of pigment. These areas were cut out of the membrane by laser microdissection, proteins were cleavaged by trypsin, and the peptides were analyzed by nLC/MS (Q-TOF). This study has identified 29 proteins and a further eight were determined by less specific “cleavage” with semitrypsin. The relative abundances of these proteins were determined using the exponentially modified protein abundance index (emPAI) where the most dominant proteins were eggshell-specific ones, such as ovocleidin-17 and ovocleidin-116. Individual areas of the cuticle membrane differ in their relative proportions of 14 proteins, where significant differences between the three quantification criteria (direct, after normalization to ovocledin-17, or to ovocledin-116) were observed in four proteins.     

以硅胶为载体通过γ-胺丙基三甲氧基硅烷偶联剂制备季铵盐类水不溶性杀菌剂的方法研究(II)

在利用硅胶表面上的羟基通过g -胺丙基硅烷把季铵盐固载到硅胶载体上制成水不溶性杀菌剂的基础上,考察了原料硅胶对制备产品杀菌性能的影响。在相同操作条件下,使用同一种原料硅胶,随着原料粒度的减小,所制备杀菌剂产品的杀菌率有所增加,但不明显;选用不同种原料硅胶合成的水不溶性季铵盐类杀菌剂的杀菌结果表明,原料比表面积越大,孔体积越小,合成产品的杀菌率越高。红外光谱证明了 -胺丙基三甲氧基硅烷已通过与硅胶表面羟基的反应键合到硅胶表面,叔胺化的硅胶中间体和产物上存在的很强的烷基峰也证明了硅胶上确实固载上了烷基官能团。交叉极化的硅核磁共振谱有效地表征了硅胶上表面羟基的反应情况,为-106处峰的基本消失证明了原料硅胶表面的硅羟基与胺丙基硅烷的键合反应比较完全。使用后的杀菌剂再生结果表明,其再生性能良好,具备重复使用的特点。     

Casein structure,self-assembly and gelation

The literature on recent studies of casein structure and function is reviewed. Where appropriate, we try to reconcile conflicting views on the issue of secondary structure in these proteins, steering a middle course where possible. A suggestion is put forward that a coarser view, treating the caseins as block copolymers may be sufficient to rationalise much of the behaviour of these proteins in self-association, adsorption and micellar assembly.     

The crowded environment of a reverse micelle induces the formation of β-strand seed structures for nucleating amyloid fibril formation

A hallmark of Alzheimer's disease is the accumulation of insoluble fibrils in the brain composed of amyloid beta (Aβ) proteins with parallel in-register cross-β-sheet structure. It has been suggested that the aggregation of monomeric Aβ proteins into fibrils is promoted by "seeds" that form within compartments of the brain that have limited solvent due to macromolecular crowding. To characterize these seeds, a crowded macromolecular environment was mimicked by encapsulating Aβ40 monomers into reverse micelles. Fourier-transform infrared spectroscopy revealed that monomeric Aβ proteins form extended β-strands in reverse micelles, while an analogue with a scrambled sequence does not. This is a remarkable finding, because the formation of extended β-strands by monomeric Aβ proteins suggests a plausible mechanism whereby the formation of amyloid fibrils may be nucleated in the human brain.