The immunophilin CYCLOPHILIN28 affects PSII-LHCII supercomplex assembly and accumulation in Arabidopsis thaliana

In plant chloroplasts,photosystem II(PSII)complexes,together with light-harvesting complex II(LHCII),form various PSII-LHCII supercomplexes(SCs).This process likely involves immunophilins,but the underlying regulatory mechanisms are unclear.Here,by comparing Arabidopsis thaliana mutants lacking the chloroplast lumen-localized immunophilin CYCLOPHILIN28(CYP28)to wildtype and transgenic complemented lines,we determined that CYP28 regulates the assembly and accumulation of PSII-LHCII SCs.Compared to the wild type,cyp28 plants showed accelerated leaf growth,earlier flowering time,and enhanced accumulation of high molecular weight PSII-LHCII SCs under normal light conditions.The lack of CYP28 also significantly affected the electron transport rate.Blue native-polyacrylamide gel electrophoresis analysis revealed more Lhcb6 and less Lhcb4 in M-LHCII-Lhcb4-Lhcb6 complexes in cyp28 versus wild-type plants.Peptidyl-prolyl cis/trans isomerase(PPIase)activity assays revealed that CYP28 exhibits weak PPIase activity and that its K113 and E187 residues are critical for this activity.Mutant analysis suggested that CYP28 may regulate PSIILHCII SC accumulation by altering the configuration of Lhcb6 via its PPIase activity.Furthermore,the Lhcb6-P139 residue is critical for PSII-LHCII SC assembly and accumulation.Therefore,our findings suggest that CYP28 likely regulates PSII-LHCII SC assembly and accumulation by altering the configuration of P139 of Lhcb6 via its PPIase activity.

Respiratory supercomplexes:structure,function and assembly

The mitochondrial respiratory chain consists of 5 enzyme complexes that are responsible for ATP generation.The paradigm of the electron transport chain as discrete enzymes diffused in the inner mitochondrial membrane has been replaced by the solid state supercomplex model wherein the respiratory complexes associate with each other to form supramolecular complexes.Defects in these supercomplexes,which have been shown to be functionally active and required for forming stable respiratory complexes,have been associated with many genetic and neurodegenerative disorders demonstrating their biomedical signifi cance.In this review,we will summarize the functional and structural signifi cance of supercomplexes and provide a comprehensive review of their assembly and the assembly factors currently known to play a role in this process.

Molecular studies of cellulose synthase supercomplex from cotton fiber reveal its unique biochemical properties

Cotton fiber is a highly elongated and thickened single cell that produces large quantities of cellulose,which is synthesized and assembled into cell wall microfibrils by the cellulose synthase complex(CSC).In this study,we report that in cotton(Gossypium hirsutum)fibers harvested during secondary cell wall(SCW)synthesis,GhCesA 4,7,and 8 assembled into heteromers in a previously uncharacterized 36-mer-like cellulose synthase supercomplex(CSS).This super CSC was observed in samples prepared using cotton fiber cells harvested during the SCW synthesis period but not from cotton stem tissue or any samples obtained from Arabidopsis.Knock-out of any of GhCesA 4,7,and 8 resulted in the disappearance of the CSS and the production of fiber cells with no SCW thickening.Cotton fiber CSS showed significantly higher enzyme activity than samples prepared from knock-out cotton lines.We found that the microfibrils from the SCW of wild-type cotton fibers may contain 72 glucan chains in a bundle,unlike other plant materials studied.GhCesA4,7,and 8 restored both the dwarf and reduced vascular bundle phenotypes of their orthologous Arabidopsis mutants,potentially by reforming the CSC hexamers.Genetic complementation was not observed when non-orthologous CesA genes were used,indicating that each of the three subunits is indispensable for CSC formation and for full cellulose synthase function.Characterization of cotton CSS will increase our understanding of the regulation of SCW biosynthesis.

Assembly mechanisms and energy transfer pathways deciphered in the cryo-EM structure of spinach photosystem Ⅱ-LHCⅡ supercomplex

Funded by the National Natural Science Foundation of China(NSFC),Ministry of Science and Technology of China,and Chinese Academy of Sciences,ajoint team of three laboratories from the Institute of Biophysics of Chinese Academy of Sciences,led by Dr.Liu Zhenfeng(柳振峰),Dr.Zhang Xinzheng(章新政)and Dr.Li Mei(李梅)respectively,solved the structure of spinach photosystem II-LHCII supercom-

Assembly mechanism and energy transfer pathways of plant photosystem II-LHCII supercomplexes discovered through cryo-electron microscopy

Funded by the National Natural Science Foundation of China,Chinese Ministry of Science and Technology,and Chinese Academy of Sciences,ajoint team of three laboratories from the Institute of Biophysics of Chinese Academy of Sciences,namely Liu Zhenfeng’s(柳振峰),Zhang

3D Fractals, Axiom of Algebra (Δn)n = +1

After having laid down the Axiom of Algebra, bringing the creation of the square root of -1 by Euler to the entire circle and thus authorizing a simple notation of the nth roots of unity, the author uses it to organize homogeneous divisions of the limited development of the exponential function, that is opening the way to the use of a whole bunch of new primary functions in Differential Calculus. He then shows how new supercomplex products in dimension 3 make it possible to calculate fractals whose connexity depends on the product considered. We recall the geometry of convex polygons and regular polygons.

聚氨大环氰基合钴超分子的转动相关时间及^(59)Co核四极耦合常数的测定——动态激光光散射的应用(英文)

对于自旋I>1 / 2的核 ,其运动的相关时间τc 以及核四极耦合常数NQCC是表征分子局部和微观动力学结构的重要参数 .然而 ,在溶液中 ,这些参数均难以测定 .该工作以聚氨大环 氰基合钴超分子体系为例 ,利用在高分子体系中广泛使用的激光光散射技术成功地测量了溶液中超分子络合物 [1 2 ]aneN4 [Co(CN) 6 ] ,[1 8]aneN6 [Co(CN) 6 ] ,[2 4]aneN8[Co(CN) 6 ] ,[1 6]aneN4 [Co(CN) 6 ] ,[2 4]aneN6 [Co(CN) 6 ]和 [3 2 ]aneN8[Co(CN) 6 ]的水合半径 ,从而根据Stokes Einstein Debye理论计算出了分子转动的相关时间τc.这些超分子的水合半径在 0 .4～ 0 .6nm之间 .对应的转动相关时间τc 在 3 .8～ 9.5×1 0 - 11s之间 .这一时间范围对于分子量在 3 0 0～ 50 0的分子 ,有相当的合理性 .进而 ,通过测量超分子在稀溶液中的纵向弛豫时间T1,结合计算出的相关时间τc,我们得到了该超分子体系中5 9Co的四极耦合常数 ,其范围在 0 .5～ 2 .2MHz之间 .我们发现 ,这些超分子在溶液中的四极耦合常数明显小于在固体状态时的值 (5～ 7MHz) .导致这一现象很可能的原因是在固体状态下5 9Co核周围的电场梯度是各向异性的 ,从而有较大的四极耦合常数值 .而在溶液中 ,由于分子的快速运动 ,各向异性被平均 。

巴尼特高等教育哲学:演变、渊源与路径

基于解释主义思想史研究,巴尼特高等教育哲学体现出三个发展阶段:理念研究由机构实体论转向教育本体论,面向超复杂性时代扬弃大学知识学根基而实现批判性存在,以“生态大学”话语重构大学本体及伦理。巴尼特高等教育哲学源于纽曼自由观、哈贝马斯解放观、巴斯卡尔批判观等前人哲学,并与后结构主义认识论、解构主义价值哲学等同时代理论进行对话。巴尼特高等教育哲学方法属于“概念定义—实践原则”结构的“世界观—方法论”范式,通过辨析概念以解释高等教育外在环境的时代性或大学机构内在主体的价值观,是围绕概念的分析哲学,是面向他者的自我本体论哲学,是高等教育话语下的价值哲学,具有时代回应性、主体针对性和价值批判性的特点。

三维超复数系上的超解析函数

文［６］中提出了三维超复数系的概念，本文研究了三维超复数系上超解析函数的等价性定理；研究了偏微商的可保持超解析性。得到了零点和零因子点的个数不变性定理。得到了超解析函数的级数展开定理。

Clifford Algebra and Hypercomplex Number as well as Their Applications in Physics

The Clifford algebra is a unification and generalization of real number, complex number, quaternion, and vector algebra, which accurately and faithfully characterizes the intrinsic properties of space-time, providing a unified, standard, elegant, and open language and tools for numerous complicated mathematical and physical theories. So it is worth popularizing in the teaching of undergraduate physics and mathematics. Clifford algebras can be directly generalized to 2n-ary associative algebras. In this generalization, the matrix representation of the orthonormal basis of space-time plays an important role. The matrix representation carries more information than the abstract definition, such as determinant and the definition of inverse elements. Without this matrix representation, the discussion of hypercomplex numbers will be difficult. The zero norm set of hypercomplex numbers is a closed set of special geometric meanings, like the light-cone in the realistic space-time, which has no substantial effect on the algebraic calculus. The physical equations expressed in Clifford algebra have a simple formalism, symmetrical structure, standard derivation, complete content. Therefore, we can hope that this magical algebra can complete a new large synthesis of modern science.

三元数及其在实数域上三维代数

三元数系是建立在实数域上的三维代数 ,与普通的多维代数不同 ,它的乘法运算不满足群的规则 .针对此问题 ,需要重新制定其运算规则 .在建立三元数与向量之间的联系之后 ,提出三元数的乘法在几何上对应于空间向量的旋转 .通过正交分解 ,将两个三元数的乘法先分解成两个同构关系 ,然后引进两类不同的群 ,再按各自群的规则分别进行计算 .亦即将不满足群规则的两个三元数的乘法计算转化成在群的规则下的运算 。

PSⅡ-LHCⅡ超分子复合物的结构与功能

PSⅡ-LHCⅡ超分子复合物是构成PSⅡ颗粒的基本单元,由PSⅡ核心复合物和LHCⅡ复合物构成。现介绍了超分子复合物的组装,PSⅡ核心复合物和LHCⅡ复合物的结构与功能,以及大量LHCⅡ和微量LHCⅡ在超分子复合物组装中的作用。

BN-PAGE在棕色脂肪线粒体呼吸链超级复合体分析中的应用

目的建立一种敏感、特异的棕色脂肪线粒体超级复合体(supercomplexes,SCs)分离及活性检测方法,有助于了解棕色脂肪线粒体的功能。方法分离并纯化小鼠棕色脂肪线粒体。采用蓝色非变性聚丙烯酰胺凝胶电泳(blue native polya-crylamide gel electrophoresis,BN-PAGE)分离不同大小的线粒体SCs。经考马斯亮蓝染色和免疫印迹分析各组分的表达情况。将凝胶置于不同的底物液孵育,根据显色反应确定线粒体复合物的酶活性。结果成功提取棕色脂肪线粒体。考马斯亮蓝染色和免疫印迹结果显示棕色脂肪线粒体SCs清晰可见,分子量在720~1236 kD之间,与预期相符。棕色脂肪线粒体SCs在复合物Ⅰ或复合物Ⅱ的底物液中呈紫色,在复合物Ⅳ的底物液中呈棕色。结论本研究建立的棕色脂肪线粒体SCs分析方法简便易行、结果直观,为肥胖及其相关代谢性疾病的研究提供了实验基础。

Dynam,c Changes of IsiA-Containing Complexes during Long-Term Iron Deficiency in Synechocystis sp, PCC 6803

Iron stress-induced protein A （IsiA）, a major chlorophyll-binding protein in the thylakoid membrane, is significantly induced under iron deficiency conditions. Using immunoblot analysis and 77 K fluorescence spectroscopy combined with sucrose gradient fractionation, we monitored dynamic changes of IsiA- containing complexes in Synechocystis sp. PCC 6803 during exposure to long-term iron deficiency. Within 3 days of exposure to iron deficiency conditions, the initially induced free IsiA proteins preferentially con- jugated to PSI trimer to form IsiA18-PS I trimers, which serve as light energy collectors for efficiently trans- mitting energy to PS h With prolonged iron deficiency, IsiA proteins assembled either into IsiA aggregates or into two other types of IsiA-PS I supercomplexes, namely IsiA-PS I high fluorescence supercomplex （IHFS） and IsiA-PS I low fluorescence supercomplex （ILFS）. Further analysis revealed a role for IsiA as an energy dissipater in the IHFS and as an energy collector in the ILFS. The trimeric structure of PS I mediated by PsaL was found to be indispensable for the formation of IHFS/ILFS. Dynamic changes in IsiA-containing complexes in cyanobacteria during long-term iron deficiency may represent an adaptation to iron limitation stress for flexible light energy distribution, which balances electron transfer between PS I and PS II, thus minimizing photooxidative damage.

你的心头也有星辰大海——带你领略呼吸的奥秘

呼吸作用是最基本的生命活动之一.20世纪初,科学家们发现了一系列可以进行电子传递的铁硫中心、卟啉环等辅基,而后又逐步鉴定出这些辅基固定在一系列的蛋白质复合物中.最近,人们发现这些蛋白质复合物并不是相互独立存在的,而是倾向于结合在一起形成呼吸体.

Coevolution study of mitochondria respiratory chain proteins:Toward the understanding of protein-protein interaction

Coevolution can be seen as the interdependency between evolutionary histories. In the context of protein evolution, functional correlation proteins are ever-present coordinated evolutionary characters without disruption of organismal integrity. As to complex system, there are two forms of protein-protein interactions in vivo, which refer to inter-complex interaction and intra-complex interaction. In this paper, we studied the difference of coevolution characters between inter-complex interaction and intra-complex interaction using ＂Mirror tree＂ method on the respiratory chain （RC） proteins. We divided the correlation coefficients of every pairwise RC proteins into two groups corresponding to the binary protein--protein interaction in intra-complex and the binary protein--protein interaction in inter-complex, respectively. A dramatical discrepancy is detected between the coevolution characters of the two sets of protein interactions （Wilcoxon test, p-value = 4.4 × 10 6）. Our finding reveals some critical information on coevolutionary study and assists the mechanical investigation of protein-protein interaction. Furthermore, the results also provide some unique clue for supramolecular organization of protein complexes in the mitochondrial inner membrane. More detailed binding sites map and genome information of nuclear encoded RC proteins will be extraordinary valuable for the further mitochondria dynamics study.

Research journey of respirasome

Respirasome,as a vital part of the oxidative phosphorylation system,undertakes the task of transferring electrons from the electron donors to oxygen and produces a proton concentration gradient across the inner mitochondrial membrane through the coupled translocation of protons.Copious research has been carried out on this lynchpin of respiration.From the discovery of individual respiratory complexes to the report of the high-resolution structure of mammalian respiratory supercomplex I1III2IV1,scientists have gradually uncovered the mysterious veil of the electron transport chain(ETC).With the discovery of the mammalian respiratory mega complex I2III2IV2,a new perspective emerges in the research field of the ETC.Behind these advances glitters the light of the revolution in both theory and technology.Here,we give a short review about how scientists‘see’the structure and the mechanism of respirasome from the macroscopic scale to the atomic scale during the past decades.

Carotenoid metabolism in mitochondrial function

Mitochondria are highly dynamic organelles that are found in most eukaryotic organisms.It is broadly accepted that mitochondria originally evolved from prokaryotic bacteria,e.g.proteobacteria.The mitochondrion has its independent genome that encodes 37 genes,including 13 genes for oxidative phosphorylation.Accumulative evidence demonstrates that mitochondria are not only the powerhouse of the cells by supplying adenosine triphosphate,but also exert roles as signalling organelles in the cell fate and function.Numerous factors can affect mitochondria structurally and functionally.Carotenoids are a large group of fat-soluble pigments commonly found in our diets.Recently,much attention has been paid in carotenoids as dietary bioactives in mitochondrial structure and function in human health and disease,though the mechanistic research is limited.Here,we update the recent progress in mitochondrial functioning as signalling organelles in human health and disease,summarize the potential roles of carotenoids in regulation of mitochondrial redox homeostasis,biogenesis,and mitophagy,and discuss the possible approaches for future research in carotenoid regulation of mitochondrial function.

运动调控线粒体呼吸链超级复合体的研究进展

线粒体呼吸链超级复合体(mitochondrial respiratory chain supercomplex, mitoSC)是线粒体内膜呼吸链上的自由复合体通过其亚基之间的相互作用形成的复合体超级组装,主要为mitoSCⅠ1+Ⅲ2+Ⅳ1-4、mitoSCⅠ1+Ⅲ2、mitoSCⅢ2+Ⅳ1-2、高分子量mitoSC (high molecular weight mitoSC, HMW mitoSC)和巨型超级复合体(mitochondrial metacomplex, mitoMC)。mitoSC已被证明具有提高呼吸链电子传递效率、减少活性氧产生的功能。在衰老的不同组织和诸多线粒体相关疾病组织中,mitoSC的种类和含量发生变化。本文通过归纳人类和哺乳动物不同组织中mitoSC的结构和功能,总结衰老、心脏疾病、2型糖尿病、癌症和基因缺陷疾病等条件下mitoSC的变化规律,重点探讨运动对mitoSC的影响及其相关调节机制,为线粒体相关疾病的运动干预提供参考。

线粒体呼吸链超超级复合物——能量大分子机器的终极形态

呼吸作用是生物体最基本最重要的生命活动。在哺乳动物中,呼吸作用(氧化磷酸化)由位于线粒体内膜上的呼吸链复合物完成。一百多年来,科学家们孜孜不倦地对线粒体呼吸链复合物进行研究,想要窥探这一能量大分子机器的全貌,但是一直未能获取该复合物蛋白质结构。我们最新的研究首次纯化出了来源于人类细胞的线粒体呼吸链超超级复合物Ⅰ_2Ⅲ_2Ⅳ_2,通过冷冻电镜技术首次成功解析了它的结构,并且提出呼吸链复合物Ⅰ、Ⅱ、Ⅲ和Ⅳ可以一起组成超大型复合物Ⅰ_2Ⅱ_2Ⅲ_2Ⅳ_2,这是呼吸链超超级复合物的终极形态。同时,我们所解析的人源呼吸链超级复合物的高分辨率结构,为攻克线粒体缺陷引起的阿尔兹海默综合征、帕金森综合征、多发性硬化、少年脊髓型共济失调以及肌萎缩性脊髓侧索硬化症等多种疾病打下了坚实的基础。