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1.
抗菌肽作为最有潜力的抗生素替代药物,其临床应用和商品化生产还十分有限。科研人员采用各种方法克服这些障碍,如引入稀有氨基酸或多肽模拟的技术以避免抗菌肽的水解,或设计更短的多肽在保持其活性的同时降低生产的成本,这些手段均基于对抗菌肽结构的了解。可见,研究抗菌肽的分子结构对改进其功能必不可少,本文将介绍抗菌肽结构与功能的关系。  相似文献   

2.
抗菌肽Cecropin及其在转基因植物抗菌中的应用   总被引:1,自引:0,他引:1  
Cecropin抗菌肽,又名天蚕素,是一类具有抗菌能力的小分子多肽,热稳定性好,抗菌谱广,在各个应用领域已经得到广泛的研究。本文就Cecropin抗菌肽结构与功能的关系、作用机制和其在转基因植物抗菌领域中的应用进行综述,转基因植物表达Cecropin抗菌肽具有应用优势和实用价值,Cecropin抗菌肽分子结构与作用机制探索的深入能进一步促进转基因植物抗菌研究的发展。  相似文献   

3.
家蚕抗菌肽的特性与应用   总被引:3,自引:0,他引:3  
家蚕抗菌肽是在抗菌、抗病毒和抗肿瘤方面具有重要的潜在应用价值的活性肽。家蚕抗菌肽抗菌谱广,由于抗菌肽有普通抗生素所不具有的一系列优点。其研究已经成热点。该文综述了冢蚕抗菌肽理化性质、结构与功能、作用机埋以及应用前景。  相似文献   

4.
蜘蛛抗菌肽研究进展   总被引:2,自引:0,他引:2  
唐兴  陈连水  李江 《生命科学》2014,(10):1090-1095
蜘蛛活性多肽研究主要集中于蜘蛛毒液中作用于离子通道的神经毒素多肽。但近年来,一些蜘蛛抗菌肽不断被分离纯化,其结构和抗菌活性也被广泛深入研究,这将成为蜘蛛活性多肽研究领域的一个新热点。在蜘蛛毒液和血液中,存在不同种类的抗菌肽,其多肽长度、结构、抗菌作用各不相同。而且,有些抗菌肽甚至具有抗肿瘤作用。概述了蜘蛛抗菌肽在结构和功能方面的研究进展。  相似文献   

5.
抗菌肽结构与功能关系及分子改造研究进展   总被引:3,自引:0,他引:3  
抗菌肽是生物体产生的一种具有抗菌活性的多肽小分子,具有广谱、特异性的抗菌、抗病毒、抗肿瘤等作用。研究表明抗菌肽的正电荷含量、疏水性和肽链结构对抗菌肽的活性至关重要的。围绕以上三个方面对抗菌肽进行分子设计和改造,以期更加有效地提高抗菌肽的抗菌活性,获得到更加高效、低毒的抗菌肽产品。该文主要通过抗菌肽结构与功能的关系,介绍抗菌肽分子设计的研究进展。  相似文献   

6.
鱼类抗菌肽的研究进展   总被引:9,自引:1,他引:8  
鱼类抗菌肽是鱼体天然免疫的重要组成部分,其结构和组成复杂多样.根据生化和结构特点,可将它们分为4种基本类型:具有疏水或双亲性α螺旋结构的抗菌肽、含多对二硫键并可形成β折叠结构的抗菌肽、组蛋白样抗菌肽和具有糖基化修饰的抗菌肽.鱼类抗菌肽多以前肽原的形式合成,通过酶解切除信号肽和羧基端酸性片段后形成有活性的成熟肽.成熟肽具有很强的抑菌活性,其最小抑制浓度多在毫摩尔水平.目前,已克隆了多个鱼类抗菌肽基因,揭示了pleurocidin等基因家族的结构及其转录调控特点.鱼类抗菌肽的抗菌机制已建立了“桶-桶板”和“地毯”样两种模型,基本阐明了抗菌肽分子结构与抗菌功能间的关系.  相似文献   

7.
昆虫抗菌肽对病原微生物作用的研究进展   总被引:31,自引:3,他引:28  
徐进署  张双全 《昆虫学报》2002,45(5):673-678
在诱导和非诱导情况下,昆虫能产生各种类型的具有体液免疫功能的小分子物质-抗菌肽,参与机体对入侵病原微生物的免疫应答反应,构成了机体独特的免疫系统和免疫机制。这类抗菌肽或抗菌蛋白也存在于其它动物。研究表明,抗菌肽对细菌、真菌、病毒和原虫都具有作用,甚至对癌细胞也具有杀伤作用。随着抗菌肽家族的不断扩大,其结构研究的深入,相继提出了一些崭新的杀菌方式和作用机制。本文从目前国内外这方面的研究入手,分析各抗菌肽的作用特点、杀菌作用模式,展望了基因工程及临床应用的前景。  相似文献   

8.
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   

9.
抗菌肽是生物体内产生的一种具有生物活性的小分子多肽,具有广谱抗细菌、抗病毒、抗真菌甚至抗癌作用。SMAP-29是来源于绵羊骨髓细胞,包含29个氨基酸的Cathelicidin类α-螺旋结构抗菌肽。SMAP-29具有多种生物活性,包括抗革兰氏阳/阴性菌、抗真菌、抗病毒、抗寄生虫、抗螺旋体、抗衣原体和中和内毒素活性,并且具有作用机制独特、快速杀灭细菌的特点。以下综述了SMAP-29抗菌肽家族的基因和蛋白结构、结构与活性关系、作用机制、生物功能、基因重组表达,重点阐述了SMAP-29结构、分子设计的必要性和基于  相似文献   

10.
抗菌肽及其功能研究   总被引:11,自引:0,他引:11  
抗菌肽是近年来发现的广泛存在于自然界的一类阳离子抗菌活性肽,越来越多的证据表明它们在宿主先天性免疫和适应性免疫中有着重要的作用。对抗菌肽的研究正不断深入。本文先从抗菌肽研究的历史背景出发,简要介绍了抗菌肽的一般特性;然后从抗菌肽的直接抗菌活性和免疫调节功能这两个方面重点阐述其在宿主防御过程中的作用,最后对抗菌肽的临床应用及前景做了一个概述。  相似文献   

11.
The growing world of expansins   总被引:34,自引:0,他引:34  
Expansins are cell wall proteins that induce pH-dependent wall extension and stress relaxation in a characteristic and unique manner. Two families of expansins are known, named alpha- and beta-expansins, and they comprise large multigene families whose members show diverse organ-, tissue- and cell-specific expression patterns. Other genes that bear distant sequence similarity to expansins are also represented in the sequence databases, but their biological and biochemical functions have not yet been uncovered. Expansin appears to weaken glucan-glucan binding, but its detailed mechanism of action is not well established. The biological roles of expansins are diverse, but can be related to the action of expansins to loosen cell walls, for example during cell enlargement, fruit softening, pollen tube and root hair growth, and abscission. Expansin-like proteins have also been identified in bacteria and fungi, where they may aid microbial invasion of the plant body.  相似文献   

12.
The increasing occurrence of drug-resistant bacterial infections in the clinic has created a need for new antibacterial agents. Natural products have historically been a rich source of both antibiotics and lead compounds for new antibacterial agents. The natural product simocyclinone D8 (SD8) has been reported to inhibit DNA gyrase, a validated antibacterial drug target, by a unique catalytic inhibition mechanism of action. In this work, we have prepared simplified flavone-based analogues inspired by the complex natural product and evaluated their inhibitory activity and mechanism of action. While two of these compounds do inhibit DNA gyrase, they do so by a different mechanism of action than SD8, namely DNA intercalation.  相似文献   

13.
Several studies have been conducted using fungi in the biological control of domestic animals and humans. In this respect, a large amount of research has been undertaken to understand the particularities of each fungus used. These fungi have been demonstrated to act on all classes of helminthes. Therefore, they should not only be called nematophagous but also helmintophagous. Evidence of enzymatic action has also revealed their mechanism of action, as well as potential metabolites that could be synthesized as bioactive molecules. Cultural barriers to the use of fungi should be broken down, since the impact on the environment is minimal. In this context, much is already known about the mechanism of interaction of these organisms with their ‘targets’. Recent research has pointed to the search for substances derived from nematophagous fungi that have demonstrated their ovicidal and/or larvicidal activity, thus being a global premise to be studied further. Crude extracts derived from nematophagous fungi of predator and ovicidal groups reduce the amount of larvae of gastrointestinal nematodes and prevent the hatching of their eggs, since they have been demonstrated to act with extracellular proteases and other enzymes. Furthermore, the activity of these enzymes has begun to be explored regarding their possible interaction with the exoskeleton of arthropods, which could emerge as an alternative method of tick control. Finally, it should be clear that nematophagous fungi in general are ‘old friends’ that are ready to the ‘fight with our old enemies’, the gastrointestinal helminth parasites harmful to human and animal health.  相似文献   

14.
Karrikins and strigolactones are novel plant growth regulators that contain similar molecular features, but very little is known about how they elicit responses in plants. A tentative molecular mechanism has previously been proposed involving a Michael-type addition for both compounds. Through structure-activity studies with karrikins, we now propose an alternative mechanism for karrikin and strigolactone mode of action that involves hydrolysis of the butenolide ring.  相似文献   

15.
Fluorescent analogues of the cholesterol absorption inhibitor (CAI), Sch 58235, have been designed and synthesized as single enantiomers. Biological testing reveals that they are potent CAIs and are suitable tools for the investigation of the azetidinone CAI mechanism of action (MOA).  相似文献   

16.
H Rochefort 《Hormone research》1987,28(2-4):196-201
The mechanism of the antiproliferative effect of nonsteroidal antiestrogens (tamoxifen, hydroxytamoxifen) is discussed from studies performed in human breast cancer cell lines. At least two types of mechanism have been evidenced. In the presence of estrogens, antiestrogens behave as classical antihormones and their inhibition of cell proliferation is likely due to inhibition of the synthesis and release of several estrogen-induced mitogens (growth factors and proteases). In the absence of estrogens (cells cultured in phenol-red-free medium), antiestrogens can still inhibit the effect of growth factors (EGF, insulin). At concentrations less than or equal to 4 microM, antiestrogens are also cytotoxic and they require accessible estrogen receptors for their action. 'Estrogen-receptor-targeted drugs' is therefore a better general term than 'antiestrogens' to describe the mechanism of action of these drugs, which can also function without inhibiting estrogen action.  相似文献   

17.
Calpains: an elaborate proteolytic system   总被引:1,自引:0,他引:1  
Calpain is an intracellular Ca(2+)-dependent cysteine protease (EC 3.4.22.17; Clan CA, family C02). Recent expansion of sequence data across the species definitively shows that calpain has been present throughout evolution; calpains are found in almost all eukaryotes and some bacteria, but not in archaebacteria. Fifteen genes within the human genome encode a calpain-like protease domain. Interestingly, some human calpains, particularly those with non-classical domain structures, are very similar to calpain homologs identified in evolutionarily distant organisms. Three-dimensional structural analyses have helped to identify calpain's unique mechanism of activation; the calpain protease domain comprises two core domains that fuse to form a functional protease only when bound to Ca(2+)via well-conserved amino acids. This finding highlights the mechanistic characteristics shared by the numerous calpain homologs, despite the fact that they have divergent domain structures. In other words, calpains function through the same mechanism but are regulated independently. This article reviews the recent progress in calpain research, focusing on those studies that have helped to elucidate its mechanism of action. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.  相似文献   

18.
植物蛋白酶抑制剂基因结构、调控及其控制害虫的策略   总被引:7,自引:1,他引:6  
程仲毅  薛庆中 《遗传学报》2003,30(8):790-796
各种不同类型的植物蛋白酶抑制剂基因已被分离,它们的特异产物(单基因或多基因组合),对昆虫体内各种生化和生理过程会产生不同程度的影响,在对昆虫和病原体防御体系中起重要作用。多种蛋白酶抑制剂重组,协同保护植物的方法,已成为害虫综合防治计划的一部分。尽管它们近期内尚不能代替化学杀虫剂,但可作为有效的替补。目前,大多数抑制剂的作用和机理正在详尽地研究中,该文综述了植物蛋白酶抑制剂的基因结构、调控与表达并讨论了培育转基因作物控制害虫的策略。  相似文献   

19.
Proteins of the PDI family: unpredicted non-ER locations and functions   总被引:15,自引:0,他引:15  
Protein disulfide isomerases (PDIs) constitute a family of structurally related enzymes which catalyze disulfide bonds formation, reduction, or isomerization of newly synthesized proteins in the lumen of the endoplasmic reticulum (ER). They act also as chaperones, and are, therefore, part of a quality-control system for the correct folding of the proteins in the same subcellular compartment. While their functions in the ER have been thoroughly studied, much less is known about their roles in non-ER locations, where, however, they have been shown to be involved in important biological processes. At least three proteins of this family from higher vertebrates have been found in unusual locations (i.e., the cell surface, the extracellular space, the cytosol, and the nucleus), reached through an export mechanism which has not yet been understood. In some cases their function in the non-ER location is clearly related to their redox properties, but in most cases their mechanism of action has still to be disclosed, although their propensity to associate with other proteins or even with DNA might be the main factor responsible for their activities.  相似文献   

20.
Receptors for auxin: will it all end in TIRs?   总被引:7,自引:0,他引:7  
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