大肠杆菌分子伴侣GroF系统及其胁助的Rubisco蛋白装配

分子伴吕协助蛋白质在体内正确组装,对分子伴侣结构和作用机制的研究不仅在生物大分子结构和功能研究中具有重要的理论意义,而且还具有广泛应用价值。大肠杆菌分子伴侣ＧｒｏＥ系统是迄今为止研究得最为透彻的分子伴侣。本文侧重总结了ＧｒｏＥ系统的作用机制及在该系统的帮助下光合细菌核酮糖１,５－二磷酸羧化／加氧酶（Ｒｕｂｉｓｃｏ）的装配情况。     

大肠杆菌分子伴侣GroE系统及其协助的Rubisco蛋白装配

分子伴侣协助蛋白质在体内正确组装,对分子伴侣结构和作用机制的研究不仅在生物大分子结构和功能研究中具有重要的理论意义,而且还具有广泛的应用价值。大肠杆菌分子伴侣GroE系统是迄今为止研究得最为透彻的分子伴侣。本文侧重总结了GroE系统的作用机制以及在该系统的帮助下光合细菌核酮糖1,5二磷酸羧化/加氧酶(Rubisco蛋白)的装配情况。     

辅分子伴侣调控热休克蛋白HSP90功能的研究

热休克蛋白90(HSP90)是一类ATPase依赖性蛋白,作为分子伴侣,可在辅分子伴侣协助下,通过自身构象改变,参与众多细胞的生物学事件,从而协助新合成蛋白的正确折叠、成功装配、功能稳定及异常蛋白的降解过程。HSP90功能的发挥依赖于辅分子伴侣及氨基末端结合的核苷酸。辅分子伴侣是一类可与分子伴侣(如,HSP90)结合并调节其功能的蛋白,通过参与ATPase循环从而调节HSP90分子伴侣的功能。近年来,辅分子伴侣的研究得到越来越多的关注,本文就辅分子伴侣调控HSP90功能的作用进行综述。     

介导新生肽链折叠的胞质分子伴侣结构、功能及作用机制研究进展

分子伴侣是一类能够识别非天然蛋白并能协助其正确折叠、组装和转运的功能蛋白。最新研究发现,在原核或真核细胞中,不同结构、不同种类的分子伴侣形成了一个复杂的折叠系统,通过这个系统,蛋白质完成了从初步合成到形成具有生物活性的三维构象的过程,避免了折叠过程中多肽链的错误折叠、蛋白沉淀和有害物质的产生。文章综述了蛋白质折叠过程中不同种类分子伴侣组件的结构、功能和作用机制的研究进展,这些分子伴侣包括Hsp70、核糖体结合因子、伴侣素、前折叠素与Hsp90,并阐述了它们在蛋白质内稳态中的作用。     

药物分子伴侣: 蛋白质折叠运输缺陷的新疗法

大量遗传性疾病的发生是由于基因突变引起蛋白质错误折叠而不能运输到作用位点，从而导致功能缺陷．近年来兴起的药物分子伴侣是恢复蛋白质折叠运输缺陷的新疗法，这类化合物一般为目的蛋白的底物类似物、受体配基或酶抑制剂等化学小分子，具细胞通透性，能在内质网中特异性识别并结合突变蛋白，校正并稳定其正确构象，协助其运输到正确位点，直接恢复突变蛋白功能，可治疗各种南蛋白质折叠运输缺陷导致的内分泌及代谢疾病．目前已报道的由药物分子伴侣恢复功能的突变蛋白主要为质膜蛋白及细胞器蛋白，如ATP结合盒转运蛋白、G-蛋白耦联受体及溶酶体酶等．大量的细胞及动物实验结果显示了药物分子伴侣的临床应用前景广阔，目前已有一例临床实验获得了成功．     

分子伴侣结构与功能的研究进展

分子伴侣是细胞内一类能够协助其他多肽进行正常折叠、组装、转运、降解的蛋白,并在 DNA的复制、转录,细胞骨架功能,细胞内的信号转导等广泛的领域,都发挥着重要的生理作用,其结构与功能异常会导致多种相关的疾病。简要综述了分子伴侣结构与功能方面的研究进展。     

植物Rubisco活化酶的研究进展

植物Rubisco活化酶广泛存在于光合生物中,是AAA＋家族成员,具有ATP酶活性,并具有对温度反应的活化Rubisco和分子伴侣的双重功能。该文重点介绍了近年来对Rubisco活化酶的分子特性、作用机制、温度等因子的影响及基因工程研究的最新进展。     

钙网蛋白与神经系统病变

钙网蛋白（calreticulin,CRT）是内质网中的一种多功能的分子伴侣,在协助蛋白质正确折叠和维持细胞Ca2＋稳态（Ca2＋信号）中发挥重要作用。近来的研究发现,钙网蛋白与神经系统病变包括阿尔茨海默氏病、帕金森病等有密切关系。     

热休克蛋白60与肿瘤关系的研究进展

HSP60是一类进化上高度保守的蛋白质家族,生理状态时协助多肽或蛋白质的正确转位,折叠和装配,起“分子伴侣”的作用,在应激状态下,HSP60过表达或异位表达,作为一种自身抗原被免疫系统识别,诱发机体的保护性免疫应答,也可作为一种信号分子,在信号转导中发挥作用,近年来研究证实HSP60在自然免疫性疾病、传染病、动脉粥样硬化及慢性感染的发病中均发挥重要的作用。     

分子伴侣及其在蛋白质折叠中的作用研究进展

蛋白质折叠是一个复杂的、动态的过程,蛋白质的折叠不是自发的,需要其他物质的帮助.了解分子伴侣在蛋白质折叠过程中的的作用,有助于进一步研究蛋白质折叠机制.本文介绍了分子伴侣及其分类,重点综述了各类分子伴侣在蛋白质折叠中的机制,并提出了研究分子伴侣在蛋白质折叠中的作用的重要意义.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.