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Stiffening of Semirigid Polymer Chains Before the Isotropic-Aniostropic Transition

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Chemical Research in Chinese Universities 2000年第2期16卷 169-175页

作者： LIN Jiaping ZHOU Dafei E China Univ Sci & Technol Dept Polymer Sci & Engn Shanghai 200237 Peoples R China

The phase behavior of a semirigid polymer manifested by the polypeptide such as poly(βphenethyl Laspartate)(PPLA) in a mixed solvent system containing a denaturant acid was studied. The obtained results suggest that there is a marked enhancement of the propensity for the semirigid polymer chain to adopt a rigid conformation upon increasing polymer concentration before the critical value for the incipience of a liquid crystal phase, which has been firmly confirmed both theoretically and experimentally. In consideration of the first order estimation of polymerpolymer interaction, a theoretical approach was attempted within the framework of a helixcoil transition model proposed by Rajan and Woo. According to the analysis, the semirigid chains could become rather rigid before reaching liquid crystal phase. Such a kind of chain stiffening effect was verified by 1H NMR and 13 C NMR measurements. The experimental results show that the PPLA molecules convert gradually from the random coil to the rigid rod conformation as polymer concentration turns higher in the isotropic phase.

关键词： polypeptide Helix-coil transition NMR

A novel plant defensin from Chinese mistletoe,Viscum coloratum (Kom.) Nakai

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Chinese Chemical Letters 2007年第1期18卷 55-58页

作者： Shi Lei Liu Xiu Bao Du Jing Lin Kong Hui Jiang Research Institute of Chemical Defense Beijing 102205 China

A novel polypeptide named as defensin CM was isolated from Chinese mistletoe, Viscum coloratura （Kom.） Nakai. The amino acid sequence was determined by the combination of Edman degradation, endoproteinase Lys-C digestion, and MALDI-TOF mass spectrometry. The primary structure was ATCSAPSGRF KGACFSSNTC SNICKTLEGL KDGHCTGLAC YCSRNC.

关键词： Viscum coloratura Mistletoe Primary structure Plant defensin polypeptide

ELECTROSPRAYING/ELECTROSPINNING OF POLY(γ-STEARYL-LGLUTAMATE):FORMATION OF SURFACES WITH SUPERHYDROPHOBICITY

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Chinese Journal of Polymer Science 2009年第1期27卷 115-120页

作者：吴健徐志康 Department of Chemistry Zhejiang University Institute of Polymer Science and Key Laboratory of Macromolecular Synthesis and Functionalization (Ministry of Education)Zhejiang University

Electrospraying/electrospinning of poly(γ-stearyl-L-glutamate) (PSLG) was investigated on a series solutions with different concentrations in *** emission scanning electron microscopy (FESEM) and attenuated Iotal reflectance Fourier transform infrared spectroscopy (FT-IR/ATR) were used to characterize the morphology and structure of the electrosprayed/electrospun polypeptide *** was found that electrospraying of PSLG with concentrations lower than 16 wt% afforded beads,while microfibers cou...

关键词： Electrospinning/electrospraying Poly(γ-stearyl-L-glutamate) polypeptide Water contact angle Superhydrophobic surface

New insights in bilirubin metabolism and their clinical implications

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World Journal of Gastroenterology 2013年第38期19卷 6398-6407页

作者： Eva Sticova Milan Jirsa Centre for Experimental Medicine Institute for Clinical and Experimental Medicine14021 Prague 4Czech Republic Third Faculty of Medicine Charles University10000 Prague 10Czech Republic

Bilirubin,a major end product of heme breakdown,is an important constituent of bile,responsible for its characteristic *** recent decades,our understanding of bilirubin metabolism has expanded along with the processes of elimination of other endogenous and exogenous anionic substrates,mediated by the action of multiple transport systems at the sinusoidal and canalicular membrane of *** inherited disorders characterised by impaired bilirubin conjugation(Crigler-Najjar syndrome typeⅠand typeⅡ,Gilbert syndrome)or transport(Dubin-Johnson and Rotor syndrome)result in various degrees of hyperbilirubinemia of either the predominantly unconjugated or predominantly conjugated ***,disrupted regulation of hepatobiliary transport systems can explain jaundice in many acquired liver *** this review,we discuss the recent data on liver bilirubin handling based on the discovery of the molecular basis of Rotor *** data show that a substantial fraction of bilirubin conjugates is primarily secreted by MRP3 at the sinusoidal membrane into the blood,from where they are subsequently reuptaken by sinusoidal membrane-bound organic anion transporting polypeptides OATP1B1 and ***1B proteins are also responsible for liver clearance of bilirubin conjugated in splanchnic organs,such as the intestine and kidney,and for a number of endogenous compounds,xenobiotics and *** of one or both OATP1B proteins thus may have serious impact on toxicity of commonly used drugs cleared by this system such as statins,sartans,methotrexate or *** liverblood cycling of conjugated bilirubin is impaired in cholestatic and parenchymal liver diseases and this impairment most likely contributes to jaundice accompanying these disorders.

关键词： Hyperbilirubinemia Hereditary jaundice UGT1A1 ABCC2 Organic anion transporting polypeptide 1B1 Organic anion transporting polypeptide 1B3

Targeted pH-responsive polyion complex micelle for controlled intracellular drug delivery

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Chinese Chemical Letters 2020年第5期31卷 1178-1182页

作者： Pan Zheng Yang Liu Jinjin Chen Weiguo Xu Gao Li Jianxun Ding Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of Sciences.Changchun 130022China University of Chinese Academy of Sciences Beijing 100049China Jilin Biomedical Polymers Engineering Laboratory Changchun 130022China

Cancer the rapy with nanoscale drug formulations has made significant progress in the past few ***,the selective accumulation and release of therapeutic agents in the lesion sites are still great *** this end,we developed a cRGD-decorated pH-responsive polyion complex(PIC)micelle for intracellular targeted delivery of doxorubicin(DOX)to upregulate tumor inhibition and reduce *** PIC micelle was self-assembled via the electrostatic interaction between the positively charged cRGD-modified poly(ethylene glycol)-block-poly(L-lysine)and the anionic acid-sensitive 2,3-dimethylmaleic anhydride-modified doxorubicin(DAD).The decoration of cRGD enhanced the cell internalization of PIC micelle through the specific recognition ofαvβ3 integrin on the membrane of tumor *** active DOX was released under intracellular acidic microenvironment after endocytosis following the decomposition of ***,the targeted PIC micelle exhibited enhanced inhibition efficacies toward hepatoma in vitro and in vivo compared with the insensitive *** smart multifunctional micelle provides a promising platform for target intracellular delivery of therapeutic agent in cancer therapy.

关键词： polypeptide Targeting pH-responsiveness Intracellular drug delivery Cancer therapy

Accelerated Ring-Opening Polymerization of α-Amino Acid N-Carboxyanhydride via Inorganic Nano-initiators

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Chinese Journal of Chemistry 2023年第19期41卷 2476-2482页

作者： Junliang Zhu Yunjie He Chenglong Ge Wenting Si Ziyuan Song Lichen Yin Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials&DevicesSoochow UniversitySuzhouJiangsu215123 China

While the accelerated polymerization of N-carboxyanhydrides (NCAs) has been utilized to synthesize versatile polypeptide materials in an efficient manner with minimized side reactions, the preparation of polypeptide-based inorganic/organic hybrid materials with the acceleration strategy remained largely unexplored. Herein, we report the accelerated ring-opening polymerization (ROP) of NCAs mediated by amine-modified inorganic nano-initiators, such as mesoporous silica nanoparticles (MSN-NH2), which is driven by the cooperative effect of the neighboring α-helical polypeptide chains in a dichloromethane (DCM)/water biphasic system. Well-defined nano-hybrids were prepared within 15 min from non-purified NCA monomers, through in situ purification and subsequent ultrafast polymerization process. NCAs can be rapidly initiated by amino groups of MSN uniformly dispersed at the interface of DCM and water, and subsequently formed the well-defined polypeptides within 15 min. The prepared inorganic/organic nano-hybrid with MSN as the core and polypeptide as the shell adopted spherical morphology and uniform size distribution due to the excellent controllability of ROP. Besides, this system is also suitable for a variety of NCAs and inorganic nano-initiators. This research allows efficient and rapid preparation of inorganic/organic nano-hybrids, and further promotes the extensive application of this material in the biomedical fields.

关键词： polypeptide N-Carboxyanhydride Inorganic organic nano-hybrids Cooperative covalent polymerization Ring-opening polymerization Kinetics Synthetic methods

The three-dimensional structure of Infectious flacherie virus capsid determined by cryo-electron microscopy

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Science China(Life Sciences) 2009年第12期52卷 1186-1191页

作者： XIE Li1,4, ZHANG QinFen2·, LU XingMeng3, DAI XinHong2, LI KunPeng2, HONG Jian1,4· & ZHOU XuePing11 Institute of Biotechnology, Zhejiang University, Hangzhou 310029, China 2 State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China 3 College of Animal Sciences, Zhejiang University, Hangzhou 310029, China 4 Center of Analysis and Measurement, Zhejiang University, Hangzhou 310029, China Institute of Biotechnology Zhejiang University Hangzhou 310029 China State Key Laboratory of Biocontrol School of Life Sciences Sun Yat-Sen University Guangzhou 510275 China College of Animal Sciences Zhejiang University Hangzhou 310029 China Center of Analysis and Measurement Zhejiang University Hangzhou 310029 China

Cryo-electron microscopy and image reconstruction were used to determine the three-dimensional structure of Infectious flacherie virus (IFV). 5047 particles were selected for the final reconstruction. The FSC curve showed that the resolution of this capsid structure was 18 ·. The structure is a psuedo T=3 (P=3) icosahedral capsid with a diameter of 302.4 · and a single shell thickness of 15 ·. The density map showed that IFV has a smooth surface without any prominent protrude or depression. Comparison of the IFV structure with those of the insect picorna-like virus-Cricket paralysis virus (CrPV)and human picornavirus-Human rhinovirus 14 (HRV 14) revealed that the IFV structure resembles the CrPV structure. The "Rossmann canyon" is absent in both IFV and CrPV particles. The polypeptide topology of IFV VP2, IFV VP3 was predicted and the subunit location at the capsid surface was further analyzed.

关键词： Infectious flacherie virus cryo-electron microscopy three-dimensional structure polypeptide folding

Elucidation of the early infection machinery of hepatitis B virus by using bio-nanocapsule

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World Journal of Gastroenterology 2016年第38期22卷 8489-8496页

作者： Qiushi Liu Masaharu Somiya Shun'ichi Kuroda Department of Biomolecular Science and Reaction The Institute of Scientific and Industrial ResearchOsaka University

Currently, hepatitis B virus(HBV), upon attaching to human hepatocytes, is considered to interact first with heparan sulfate proteoglycan(HSPG) via an antigenic loop of HBV envelope S protein. Then, it is promptly transferred to the sodium taurocholate cotransporting polypeptide(NTCP) via the myristoylated N-terminal sequence of pre-S1 region(from Gly-2 to Gly-48, HBV genotype D), and it finally enters the cell by endocytosis. However, it is not clear how HSPG passes HBV to NTCP and how NTCP contributes to the cellular entry of HBV. Owing to the poor availability and the difficulty of manipulations, including fluorophore encapsulation, it has been nearly impossible to perform biochemical and cytochemical analyses using a substantial amount of HBV. A bio-nanocapsule(BNC), which is a hollow nanoparticle consisting of HBV envelope L protein, was efficiently synthesized in Saccharomyces cerevisiae. Since BNC could encapsulate payloads(drugs, genes, proteins) and specifically enter human hepatic cells utilizing HBV-derived infection machinery, it could be used as a model of HBV infection to elucidate the early infection machinery. Recently, it was demonstrated that the N-terminal sequence of pre-S1 region(from Asn-9 to Gly-24) possesses low p H-dependent fusogenic activity, which might play a crucial role in the endosomal escape of BNC payloads and in the uncoating process of HBV. In this minireview, we describe a model in which each domain of the HBV L protein contributes to attachment onto human hepatic cells through HSPG, initiation of endocytosis, interaction with NTCP in endosomes, and consequent provocation of membrane fusion followed by endosomal escape.

关键词： Bio-nanocapsule Endosomal escape Hepatitis B virus Heparan sulfate proteoglycan Sodium taurocholate cotransporting polypeptide

Diabetic neuropathy: An evaluation of the use of quercetin in the cecum of rats

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World Journal of Gastroenterology 2013年第38期19卷 6416-6426页

作者： Paulo Emilio Botura Ferreira Cláudia Regina Pinheiro Lopes Angela Maria Pereira Alves der Paulo Belato Alves David Robert Linden Jacqueline Nelisis Zanoni Nilza Cristina Buttow Department of Morphological Sciences Universidade Estadual de MaringáMaringáPR. CEP 87020-900Brazil Department of Physiology and Biomedical Engineering and Enteric NeuroScience Program Mayo Clinic College of MedicineRochesterMN 55905United States

AIM:To investigate the effect of quercetin supplementation on the myenteric neurons and glia in the cecum of diabetic ***:Total preparations of the muscular tunic were prepared from the ceca of twenty-four rats divided into the following groups:control(C),control supplemented with quercetin(200 mg/kg quercetin body weight)(CQ),diabetic(D)and diabetic supplemented with quercetin(DQ).Immunohistochemical double staining technique was performed with HuC/D(general population)/nitric oxide synthase(nNOS),HuC-D/S-100and *** analysis of the general neuronal population HuC/D-IR,the nNOS-IR(nitrergic subpopulation)and the enteric glial cells(S-100)was performed,and the morphometry and the reduction in varicosity population(VIP-IR)in these populations were ***:Diabetes promoted a significant reduction(25%)in the neuronal density of the HuC/D-IR(general population)and the nNOS-IR(nitrergic subpopulation)compared with the C *** also significantly increased the areas of neurons,glial cells and VIP-IR *** with quercetin in the DQ group prevented neuronal loss in the general population and increased its area(P<0.001)and the area of nitrergic subpopulation(P<0.001),when compared to C *** induced a VIP-IR and glial cells areas(P<0.001)in DQ group when compared to C,CQ and D ***:In diabetes,quercetin exhibited a neuroprotective effect by maintaining the density of the general neuronal population but did not affect the density of the nNOS subpopulation.

关键词： Diabetes Myenteric plexus Neuroprotection Neuronal nitric oxide synthase Vasoactive intestinal polypeptide Enteric glia