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以海洋微生物溶菌酶（ⅧL）为研究对象,分别检验几种表面剂对MBL活性的影响,着重研究烷基多苷（APG）对其活性的影响。结果表明,APG与阳离子烷基多苷（矾PG）分别提高MBL相对酶活性为21％,15％,SDS降低该酶活性约为15％,Tween20和Tween80对MBL活性的影响不明显。MBL含量大于5．0mg／mL时,对大肠杆菌、金黄色葡萄、白色念珠球菌有抑菌作用。0．5％～1．5％的APG无明显抑菌作用。将5．0mg／mMBL与1．0mg／mLAPG复配后（简称CEP）,发现APG能明显增强MBL抑菌作用,CEP具有较好地杀菌作用;CEP在54℃培养箱中放置14d后,其杀菌率保持不变,说明CEP的杀菌性能的稳定性良好。 相似文献
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To develop novel antibiotic peptides useful as therapeutic drugs, short model peptides rich in Leu and Lys were designed by changing not only the net positive charge by Lys-deletion but also in the hydrophobic helix region by Leu-deletion from a peptide analogue of cecropin A (1–8)-magainin 2 (1–12) (CA-MA) known as P5. In particular, one peptide (P6), which was obtained by deleting Lys residues (positions 1, 3, 5, 9, 10, 13, 14) and Leu residues (positions 4, 7, 8, 11, 12, 15) and keeping Pro (position 6) and Trp (position 2), showed a strong antimicrobial and antitumor activity at 0.2–3.1 M without hemolytic activity against human erythrocyte cells. Furthermore, P6 causes significant morphological alterations of the bacterial surfaces at 3.1 M as shown by scanning electron microscopy. 相似文献
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Ghufran Barnawi Michael Noden Robert Taylor Chuda Lohani David Beriashvili Michael Palmer Scott D. Taylor 《Peptide Science》2019,111(1)
Daptomycin is an important Ca2+‐dependent cyclic lipodepsipeptide antibiotic used to treat serious gram‐positive infections. The search for daptomycin analogs with improved activity and their application as tools for studying its mechanism of action has prompted us to develop an entirely Fmoc solid phase approach to the synthesis of daptomycin analogs. Key to the success of this approach was the development of conditions that allowed for the formation of the ester bond on resin‐bound peptides consisting of residues 1‐10 and the decanoyl lipid tail. The esterification reaction proceeded more efficiently on Tentagel resin as opposed to standard polystyrene resin. This approach was used to synthesize a series of analogs in which each position of Dap‐E12‐W13, a relatively active daptomycin analog, was individually substituted by alanine. Only positions 2, 6, and 11 were found to be amenable to substitution by alanine in that the corresponding alanine analogs were only 1.5‐ to 4‐fold less active than Dap‐E12‐W13. We also found that the daptomycin analog, Dap‐K6‐E12‐W13, exhibits in vitro activity approaching that of daptomycin at physiological Ca2+ concentration. Studies with Dap‐K6‐E12‐W13 and model liposomes indicate that this analog interacts with membranes by the same mechanism as daptomycin. This analog is currently being used as a lead for the development daptomycin analogs with improved activity. 相似文献
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通过缬氨酸和精氨酸的交替连接形成β-发卡结构的两条侧链,D-脯氨酸和甘氨酸形成β-转角单元以及侧链末端的两个半胱氨酸连接形成一个二硫键,来设计得到全新的由16残基构成的β-发卡抗菌肽VR。对设计得到的抗菌肽VR的生物学活性进行了检测,主要测定了新型β-发卡抗菌肽VR的最小杀菌浓度、对红细胞的溶血活性、杀菌动力学和盐敏感性。结果发现,VR和蜂毒素具有相似的杀菌活性,而溶血活性远低于蜂毒素,这表明VR比蜂毒素具有更高的细胞选择性。在NaCl的浓度低于100 mmol/L时,VR的杀菌活性没有受到影响;在NaCl的浓度为100 mmol/L时,VR具有50%的杀菌活性。综上可见,VR具有较优异的生物学活性,拥有成为抗生素替代物的发展潜力。 相似文献
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Kalkena Sivanesam Brandon L. Kier Samuel D. Whedon Champak Chatterjee Niels H. Andersen 《Journal of peptide science》2017,23(12):899-906
Designing new antimicrobial peptides (AMPs) focuses heavily on the activity of the peptide and less on the elements that stabilize the secondary structure of these peptides. Studies have shown that improving the structure of naturally occurring AMPs can affect activity and so here we explore the relationship between structure and activity of two non‐naturally occurring AMPs. We have used a backbone‐cyclized peptide as a template and designed an uncyclized analogue of this peptide that has antimicrobial activity. We focused on beta‐hairpin‐like structuring features. Improvements to the structure of this peptide reduced the activity of the peptide against gram‐negative, Escherichia coli but improved the activity against gram‐positive, Corynebacterium glutamicum. Distinctions in structuring effects on gram‐negative versus gram‐positive activity were also seen in a second peptide system. Structural improvements resulted in a peptide that was more active than the native against gram‐positive bacterium but less active against gram‐negative bacterium. Our results show that there is not always a correlation between improved hairpin‐structuring and activity. Other factors such as the type of bacteria being targeted as well as net positive charge can play a role in the potency of AMPs. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
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Antimicrobial peptides versus parasitic infections? 总被引：3，自引：0，他引：3
Reports of antimicrobial peptides generally have evaluations of their antibacterial and antifungal activities. By contrast, little is known of their activities against protozoan and metazoan parasites. In vitro antiparasitic assays suggest that antimicrobial peptides could represent a powerful tool for the development of novel drugs to fight the parasite in the vertebrate host, or to complement current therapeutic strategies. 相似文献
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Rodrigo González Lorena Mendive‐Tapia María B Pastrian Fernando Albericio Rodolfo Lavilla Osvaldo Cascone Nancy B Iannucci 《Journal of peptide science》2016,22(2):123-128
Antimicrobial peptides are valuable agents to fight antibiotic resistance. These amphipatic species display positively charged and hydrophobic amino acids. Here, we enhance the local hydrophobicity of a model peptide derived from human lysozyme (107RKWVWWRNR115) by arylation of its tryptophan (Trp) residues, which renders a positive effect on Staphylococcus aureus and Staphylococcus epidermidis growth inhibition. This site‐selective modification was accessed by solid‐phase peptide synthesis using the non‐proteinogenic amino acid 2‐aryltryptophan, generated by direct C‐H activation from protected Trp. The modification brought about a relevant increase in growth inhibition: S. aureus was fully inhibited by arylation of Trp 112 and by only 10% by arylation of Trp 109 or 111, respect to the non‐arylated peptide. On the other hand, S. epidermidis was fully inhibited by the three arylated peptides and the parent peptide. The minimum inhibitory concentration was significantly reduced for S. aureus depending on the arylation site. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
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Antimicrobial peptides (AMPs), with their extraordinary properties, such as broad-spectrum activity, rapid action and difficult development of resistance, have become promising molecules as new antibiotics. Despite their various mechanisms of action, the interaction of AMPs with the bacterial cell membrane is the key step for their mode of action. Moreover, it is generally accepted that the membrane is the primary target of most AMPs, and the interaction between AMPs and eukaryotic cell membranes (causing toxicity to host cells) limits their clinical application. Therefore, researchers are engaged in reforming or de novo designing AMPs as a ‘single-edged sword’ that contains high antimicrobial activity yet low cytotoxicity against eukaryotic cells. To improve the antimicrobial activity of AMPs, the relationship between the structure and function of AMPs has been rigorously pursued. In this review, we focus on the current knowledge of α-helical cationic antimicrobial peptides, one of the most common types of AMPs in nature. 相似文献
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Nagachaitanya Bhagavathula Venkateshwarlu Meedidoddi Simon Bourque Reshmy Vimaladevi Santoshkumar Kesavakurup Dayanandan Selvadurai Sameer Shrivastava Chandrashekara Krishnappa 《Archives of insect biochemistry and physiology》2017,94(4)
Antimicrobial peptides (AMPs) from cuticular extracts of worker ants of Trichomyrmex criniceps (Mayr, Hymenoptera: Formicidae) were isolated and evaluated for their antimicrobial activity. Eight peptides ranging in mass from 804.42 to 1541.04 Da were characterized using a combination of analytical and bioinformatics approach. All the eight peptides were novel with no similarity to any of the AMPs archived in the Antimicrobial Peptide Database. Two of the eight novel peptides, the smallest and the largest by mass were named Crinicepsin‐1 and Crinicepsin‐2 and were chemically synthesized by solid phase peptide synthesis. The two synthetic peptides had antibacterial and weak hemolytic activity. 相似文献
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A. A. Romani M. C. Baroni S. Taddei F. Ghidini P. Sansoni S. Cavirani C. S. Cabassi 《Journal of peptide science》2013,19(9):554-565
Antimicrobial‐peptide‐based therapies could represent a reliable alternative to overcome antibiotic resistance, as they offer potential advantages such as rapid microbicidal activity and multiple activities against a broad spectrum of bacterial pathogens. Three synthetic antimicrobial peptides (AMPs), AMP72, AMP126, and also AMP2041, designed by using ad hoc screening software developed in house, were synthesized and tested against nine reference strains. The peptides showed a partial β‐sheet structure in 10‐mM phosphate buffer. Low cytolytic activity towards both human cell lines (epithelial, endothelial, and fibroblast) and sheep erythrocytes was observed for all peptides. The antimicrobial activity was dose dependent with a minimum bactericidal concentration (MBC) ranging from 0.17 to 10.12 μM (0.4–18.5 µg/ml) for Gram‐negative and 0.94 to 20.65 μM (1.72‐46.5 µg/ml) for Gram‐positive bacteria. Interestingly, in high‐salt environment, the antibacterial activity was generally maintained for Gram‐negative bacteria. All peptides achieved complete bacterial killing in 20 min or less against Gram‐negative bacteria. A linear time‐dependent membrane permeabilization was observed for the tested peptides at 12.5 µg/ml. In a medium containing Mg2+ and Ca2+, the peptide combination with EDTA restores the antimicrobial activity particularly for AMP2041. Moreover, in combination with anti‐infective agents (quinolones or aminoglycosides) known to bind divalent cation, AMP126 and AMP2041 showed additive activity in comparison with colistin. Our results suggest the following: (i) there is excellent activity against Gram‐negative bacteria, (ii) there is low cytolytic activity, (iii) the presence of a chelating agent restores the antimicrobial activity in a medium containing Mg2+ and Ca2+, and (iv) the MBC value of the combination AMPs–conventional antibiotics was lower than the MBC of single agents alone. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
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胡蜂毒肽(mastoparans, MP)是一类昆虫源的α-螺旋阳离子抗菌肽,具有广谱的抗微生物活性,对细菌、真菌、病毒及寄生虫的生长均有一定的抑制作用。通过氨基酸替换、肽段结构修饰、肽链环化及剂型改造等多种方法进行多肽改造,可增强胡蜂毒肽的生物学活性和靶向性,并降低其毒性。本文对胡蜂毒肽的结构、生物学功能及其修饰改造方法进行综述,并对以胡蜂毒肽为基础的抗菌药物研发进行了展望,为胡蜂毒肽作为新型抗微生物药物的研究提供了参考。 相似文献
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Novel antimicrobial peptides are valuable molecules for developing anti‐infective drugs to counteract the contemporary spread of microbial drug‐resistance. Here we focus on a novel peptide (RKWVWWRNR‐NH2) derived from the fragment 107–115 of the human lysozyme that displays a 20‐fold increase in anti‐staphylococcal activity. The conformational analysis of this peptide and its interaction with model lipidic phases—as assayed by circular dichroism and fluorescence spectroscopy—show a noteworthy spectral change, which might be related to its anti‐staphylococcal activity. The secondary structure of peptide [K108W111] 107–115 hLz was dramatically affected through a single substitution at position 111 (Ala by Trp). Therefore, this conformational change might improve the interaction of the novel peptide with the bacterial plasma membrane. These results highlight the role of peptide secondary structure and the distribution of polar/nonpolar residues for the effective interaction of this peptide with the bacterial plasma membrane, a key step for triggering its lethal effect. This knowledge may contribute to the rational design of a new generation of antimicrobial peptides with increased efficacy developed from natural sources by simple screening tools. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 49–57, 2014. 相似文献
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通过比较6种不同型号的大孔吸附树脂对家蝇蛋白的吸附解吸特性,发现D101大孔吸附树脂的性能优于其他5种,吸附流速、浓度影响大孔吸附树脂的动态吸附性能。D101大孔吸附树脂对未经诱导的家蝇蛋白的吸附量可达217．18mg／g（以干树脂总量为基准）,洗脱率为76．48％。吸附后的大孔吸附树脂用15％、35％、55％的乙醇溶液阶段洗脱,各洗脱组分的疏水性逐渐增大,蛋白质含量也明显增加。用E.coli、S．aureus和B．subtilis对各洗脱组分进行抑菌活性测定,抑菌活性随洗脱组分的疏水性增加而增大。测得55％乙醇洗脱组分的抑菌活性最大,其中对E.coli的抑菌圈直径达5．8mm。 相似文献
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铰链结构,又称铰链区或转角,是部分抗菌肽序列中存在的一种特殊结构。但目前抗菌肽结构的研究多集中于标准的α-螺旋和β-折叠二级结构,对于铰链结构及其作用总结较少。铰链结构对抗菌肽生物活性有重要影响,主要原因是铰链结构能够提高抗菌肽的结构灵活性,促进其对细菌细胞膜的破坏作用或与胞内作用靶点的结合效率,进而提高抗菌肽的抗菌活性。同时,降低的抗菌肽结构刚性,消减了抗菌肽对真核细胞的毒性。文中结合了笔者课题组相关工作,就铰链结构特点、对抗菌肽生物活性的影响以及在抗菌肽分子设计方面的应用进行了综述,以期为新型抗菌肽的设计和开发提供参考。 相似文献
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为了提高黄粉虫抗菌肽基因tmAMP1m在大肠杆菌中的表达量,研究了培养温度、诱导时间及IPTG浓度等不同条件对HIS-TmAMP1m融合蛋白表达量和活性的影响。通过Tricine-SDS-PAGE分析确定最佳表达条件,同时,通过琼脂孔穴扩散法检测其抑菌活性。结果表明,含有重组质粒的大肠杆菌在37℃,使用终浓度为0.1 mmol/L IPTG培养4 h时,融合蛋白表达量较高,可占细菌总蛋白40%以上,抗菌活性最好。用Ni2+亲和层析纯化获得较纯的融合蛋白,Western blotting分析表明其能与His单克隆抗体起特异性反应。诱导表达的融合蛋白对宿主菌生长产生一定程度抑制。融合蛋白经100℃煮沸10 h,在20℃反复冻融10次,与强酸强碱缓冲液、不同的有机溶剂和蛋白酶混合后都具有极强的稳定性,仍然表现出良好的抗菌活性。此外,最小抑菌浓度(MIC)测定结果表明,融合蛋白对5种菌具有良好的抗菌活性。研究结果为昆虫抗菌肽推广应用和进一步研究奠定了基础。 相似文献
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This review examines the question of whether exercise can be used as an experimental model to further our understanding of innate antimicrobial peptides and proteins (AMPs) and their role in susceptibility to infection at mucosal surfaces. There is strong evidence to suggest that AMPs, in combination with cellular and physical factors, play an important role in preventing infection. Although AMPs act directly on microorganisms, there is increasing recognition that they also exert their protective effect via immunomodulatory mechanisms, especially in noninflammatory conditions. Further studies that manipulate physiologically relevant concentrations of AMPs are required to shed light on the role they play in reducing susceptibility to infection. Evidence shows that in various form prolonged and/or exhaustive exercise is a potent modulator of the immune system, which can either sharpen or blunt the immune response to pathogens. The intensity and duration of exercise can be readily controlled in experimental settings to manipulate the degree of physical stress. This would allow for an investigation into a potential dose-response effect between exercise and AMPs. In addition, the use of controlled exercise could provide an experimental model by which to examine whether changes in the concentration of AMPs alters susceptibility to illness. 相似文献