The total synthesis of natural cyclopeptide auyuittuqamide A / 药学实践杂志

Objective To synthesize the natural cyclopeptide auyuittuqamide A by Fmoc-based solid phase linear synthesis and liquid phase cyclization. Methods Using 2-chlorotriphenylmethyl chloride (CTC) resin as the solid support, 1,3-diisopropylcarbodiimide (DIC) and 1-hydroxybenzotriazole (HOBt) as the condensing agents, 9-fluorenylmethoxycarbonyl (Fmoc) to protect amino acids were assembled in sequence, and then the linear peptide bearing the protected groups was obtained in presence of trifluoroethanol (TFE) cutting reagent. The protected linear peptide was cyclized with the aid of benzotriazole hexafluorophosphate (PyBOP) and 1-hydroxybenzotriazole (HOBt) in dichloromethane (DCM) solution, followed by trifluoroacetic acid (TFA) deprotection to obtain the cyclic peptide, auyuittuqamide A that was purified by preparative HPLC and characterized by HR-MS and 500MHz 1H-NMR. Results The purity of auyuittuqamide A was more than 95% and the total yield was 5.48%. Conclusion This method has simple synthesis steps and high yield. It is the first to establish a fully synthesis method for the natural cyclic peptide auyuittuqamide A, which lays the foundation for further research of auyuittuqamide A.

Regulación de la actividad enzimática de la NMNAT de Leishmania braziliensis por péptidos representativos de su extremo N-terminal / Regulation of the enzymatic activity of the NMNAT of Leishmania braziliensis by representative peptides derived from its N-terminus end / Regulação da atividade enzimática do NMNAT de Leishmania braziliensis por peptídeos representativos derivados de sua extremidade N-terminal

Resumen El parásito intracelular Leishmania braziliensis es el agente causal de la leishmaniasis cutánea, enfermedad endémica de zonas tropicales, cuyos tratamientos farmacológicos son tóxicos y para la cual no se dispone de una vacuna en la actualidad. Por esta razón, el estudio de las proteínas relacionadas con el metabolismo energético del parásito es relevante dada su importancia para la supervivencia del mismo. En este estudio, utilizando como secuencia plantilla los primeros 18 residuos del extremo N-terminal de la proteína nicotinamida/ nicotinato mononucleótido adenilil transferasa de L. braziliensis (Lb-NMNAT), se sintetizaron péptidos implementando la estrategia Fmoc/ tert-Butilo en una resina Rink amida MBHA. Los péptidos se purificaron por cromatografía en columna C18 y se caracterizaron mediante RP-HPLC. La proteína recombinante 6xHisLb-NMNAT se expresó en células Escherichia coli M15 y se purificó parcialmente empleando cromatografía de afinidad a metales inmovilizados. De esta proteína se confirmó su actividad enzimática a través de ensayos enzimáticos directos analizados por RP-HPLC. Los péptidos sintetizados se utilizaron para evaluar su efecto sobre la actividad enzimática de la proteína 6xHisLb-NMNAT, observándose una modulación diferencial, lo cual resulta promisorio para el diseño de herramientas quimioterapéuticas basadas en la secuencia N-terminal de la proteína Lb-NMNAT.

Abstract The intracellular parasite Leishmania braziliensis is the etiological agent of cutaneous leishmaniasis, an endemic disease in the tropics, whose pharmacological treatments are toxic and for which there is currently no vaccine. For this reason, the study of proteins related to the energy metabolism of the parasite is relevant given its importance for its survival. In this study, based on the first 18 residues of the N-terminal end of the nicotinamide/nicotinate mononucleotide adenylyl transferase protein from L. braziliensis (Lb-NMNAT) as a template, peptides were synthesized implementing the Fmoc/tert-Butyl strategy in a Rink amide MBHA resin. The peptides were purified by C18 column chromatography and characterized by RP-HPLC. The recombinant 6xHisLb-NMNAT protein was expressed in Escherichia coli M15 cells and partially purified using immobilized metal affinity chromatography. The enzymatic activity of the protein was confirmed through direct enzymatic assays analyzed by RP-HPLC. The synthesized peptides were used to evaluate their effect on the enzymatic activity of the 6xHisLb-NMNAT protein, observing a differential modulation, which is promising for the design of chemotherapeutic tools based on the N-terminal sequence of the Lb-NMNAT protein.

Resumo O parasita intracelular Leishmania braziliensis é o agente causador da leishmaniose tegumentar, doença endêmica nos trópicos, cujos tratamentos farmacológicos são tóxicos e para a qual não existe vacina atualmente. Por este motivo, o estudo de proteínas relacionadas ao metabolismo energético do parasita é relevante dada a sua importância para a sua sobrevivência. Neste estudo, usando os primeiros 18 resíduos da extremidade N-terminal da proteína adenilil transferase de nicotinamida/mononucleotídeo nicotinato de L. braziliensis (Lb-NMNAT) como uma sequência modelo, os peptídeos foram sintetizados implementando a estratégia Fmoc/tert-Butil em uma resina Rink amida MBHA. Os peptídeos foram purificados por cromatografia em coluna C18 e caracterizados por RP-HPLC. A proteína recombinante 6xHisLb-NMNAT foi expressa em células de Escherichia coli M15 e parcialmente purificada usando cromatografia de afinidade com metal imobilizado. Desta proteína, sua atividade enzimática foi confirmada por meio de ensaios enzimáticos diretos analisados por RP-HPLC. Os peptídeos sintetizados foram utilizados para avaliar seu efeito na atividade enzimática da proteína 6xHisLb-NMNAT, observando uma modulação diferencial, o que é promissor para o projeto de ferramentas quimioterápicas baseadas na sequência N-terminal da proteína Lb-NMNAT

Total synthesis and structure-activity relationship of cyclic peptide antibiotic teixobactin:research advances / 国际药学研究杂志

Teixobactin, a cyclic-peptide antibiotic, destroys the cell walls of Gram-positive bacteria. It is therefore difficult for bacteria such as meticillin-resistant Staphylococcus aureus to develop resistance to it. Many scholars have studied the structure-activity relationship (SAR) of teixobactin. After reviewing the reports related to the discovery, structure, total synthesis and SAR of teixobactin, we found that the total synthesis of teixobactin was very difficult. The N-terminal methyl modification, ester bond and allo-End were unnecessary for the activity, the configuration of amino acids at the positions 1, 4, 5 and 8 could greatly influence the antibacterial activity, and the substitution of the amino acids at the 3, 4, 9 and 10 positions by Lys could retain the antibacterial activity.

Enhanced production and organic solvent stability of a protease fromBrevibacillus laterosporus strain PAP04

A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74%) followed by acetone (63%) and chloroform (54.8%). In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50%) concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media.

Activities of α-conotoxin TxID isomers on human nicotinic acetylcholine receptors / 中国药科大学学报

@#To investigate activities of three isomers of α-conotoxin TxID on human α3β4 and α6/α3β4 nicotinic acetylcholine receptors(nAChRs). The three isomers of α-conotoxin TxID were synthesized using solid phase Fmoc chemistry and fully folded by two-step oxidations. Human α3β4 and α6/α3β4 nAChRs were expressed in oocytes of Xenopus laevis, which were used for bioassay of the three isomers, including inhibition and washout reversibility. There were obvious differences between the inhibition potency of each isomers at human α3β4 and α6/α3β4 nAChRs. The blocking was reversible and washout rapidly. The most potent isomer is the globular form with an IC50 of 9. 3 nmol/L on human α3β4 and α6/α3β4 nAChRs respectively. The 2nd potent isomer was the ribbon form with much less potency, which had an IC50 of > 5 μmol/L. The bead isomer had little or no block on human α3β4 and α6/α3β4 nAChRs with an IC50 of > 10 μmol/L. The three isomers of α-conotoxin TxID were synthesized successfully with two pairs of desired disulfide bond. Inhibition activities of the 3 isomers on human α3β4 and α6/α3β4 nAChRs were obtained respectively, which would be basis for new marine drug development of α-conotoxin TxID.

Recent progress in the improvement of the coupling efficiency of "difficult sequences" in peptide synthesis / 药学学报

Even though chemistry is now in place that potentially allows high coupling efficiencies to be attained, successful coupling is usually a challenge when so-called "difficult sequences" is encountered in peptide synthesis. Some factors that affect the coupling efficiency have been discussed and related methods to overcome those obstacles have been introduced in present review. All suggestions proposed here are valuable and also feasible to improve the coupling completeness in both liquid-phase or solid-phase peptide synthesis.

The antitumor activity of ND 100 peptide / 中国药理学通报

Aim: To study the antitumor activity of ND 100. Methods: ND 100 containing 8 amino acid residues was synthesized by solution phase methods. The molecular weight of ND 100 was 846.9. The inhibition of tumorigenesis in vivo was tested by treatment on tumor mice, meanwhile the effect of ND 100 on the numbers of erythrocyte and leukocyte was measured. Results: ND 100 exerted strong dose-dependent inhibition on the growth of H22 heptoma, S180 sarcoma and Lewis lung carcinoma. The least efficient dose was 2.5 mg·kg-1. When higher dose (15 mg·kg-1) was used, the inhibition rate of these 3 kinds of tumors reachesd above 70%. ND 100 had no effect on erythrocyte and leukocyte of mice. Conclusion: ND 100 has strong antitumor activity in vivo.

Prediction,synthesis and characteristics of B-cell epitopes of CSFV envelope glycoprotein E2 / 中国免疫学杂志

Objective:Study on characteristics of two synthesizd peptides based on CSFV E2 protein. Methods:B cell epitopes of CSFV E2 antigen were predicted using accessibility and flexibility schemes, associated with antigenicity , secondary structure and multiple sites prediction. Two antigen peptides (Pep1 and Pep2) have been designed and synthesized and their reactivety were detected with 8 McAbs and antiserum against mE2 protein, then the peptides were conjugated with BSA and immunized rabbits respectively. Results:Both Pep1 and Pep2 could react with antiserum and McAb A11, Pep2 could interact with McAbD5 and McAbD8. Only Pep1 BSA conjugate can stimulate high level and specific antibodies.Conclusion: The peptide1 has good antigenicity.

Epitope analysis of a novel Homo spains synapse associated protein(FRG4) and preparation of antibody / 中国免疫学杂志

Objective:To analyze a novel epitope of Homo sapiens synapse associated protein and synthesize polyclonal antibody.Methods:FRG4 full-length sequence was obtained by PCR from human fetal liver library;by bioinformatics to detect the second structure of amino acids encoded by FRG4 and its epitope and motifs;by solid-phase peptide synthesis method to synthesize FRG4 peptides,then peptides were immunized to rabbits;by immunohistory to detect the expression of FRG4 in HepG_2 cells.Results:Select 13-peptides PKLVKEEVFWRNY by bioinformatics to synthesize rabbit anti-human FRG4 polyclonal antibody.Antibody purity was 82.79% and antibody dilution was 1∶16 000 detected by ELISA.The antibody had a good reaction and speciality in Western blot,it was mainly expressed in cytoplasm of HepG_2 cells.Conclusion:A novel Homo sapiens synapse associated protein(FRG4) antibody was synthesized successfully.

The effect of synthetic osteogenic growth peptide on tibia fracture healing in rabbits / 中华骨科杂志

Objective To evaluate the effects of the synthetic osteogenic growth peptide (sOGP) on the healing of tibial fractures in rabbits. Methods Fifty two tibial fracture models were produced in the tibiae of New Zealand white rabbits and immobilized with a 2 mm diameter Kirschner wire as intramedullary nail and grouped by random. sOGP was administered to experimental animals by intravenous injection (0.5 ?g?kg-1 ?d-1) from the first day after surgery until the day before sacrifice, while the control animals were injected with saline solution. 3-5 rabbits from each group were killed at 1, 2, 3, 4, 6 weeks after fracture. The serum was obtained to determine the level of ALP and BGP by biochemistry and RIA respectively. The bone mineral density at fracture healing site was detected by DXA, the anteroposterior and lateral radiographs were taken, the histological examination was done and quantitative analysis of the callus area and the relative amounts of bone, cartilage, and fibrous tissue in the callus of each section were calculated by computer program. The 6 weeks tibial sample were tested biomechanically by universal material test machine. Results The serum ALP, BGP level were higher in sOGP injected groups than those in the controls. All tibia osteotomies healed uneventfully on radiograph. The area of the external callus was larger in the experimental groups than that in controls at 3,4 weeks after fracture; the average area was 265.44 mm2 at 3 weeks, 233.10 mm2 at 4 weeks in the experimental groups compared with that of 209.95 mm2 at 3 weeks and 209.21 mm2 at 4 weeks in the controls. The average bone mineral density at fracture healing site was slightly greater in the experimental group at 3,4,6 weeks, and the difference of the bone mineral density at 4 weeks has statistical significance (P

Effect of RDP1258 on survival of rat cardiac allograft / 中华器官移植杂志

Objective To investigate the effects of RDP1258 on survival of rat cardiac allograft. Methods RDP1258 was synthesized and the model of rat heart abdominal transplantation was established. Animals were divided into four groups. Group 1 received no immunosuppression. Group 2 received CsA alone. Group 3 received RDP1258 alone. Group 4 received RDP1258 and subtherapeutic CsA. In all cases RDP1258 was administrated intraperitoneally and CsA was gavaged. Light and electron microscopic examinations were taken . Transplanted hearts were monitored daily by direct palpation. Results The purity of synthesized RDP1258 was over 95 % and the molecular weight was in accord with theoretical value. The histology and the ultrastructure changed little in grafts in group 3 and group 4. Survival of rat cardiac allograft was significantly prolonged in group 4. Conclusions RDP1258 can suppress acute rejection. Perioperative administration of RDP1258 in combination with CsA can significantly prolong survival of rat cardiac allograft.