Insights into the subunit interactions of the chloroplast ATP synthase

Subunit interactions of the chloroplast F0F1- ATP synthase were studied using the yeast two-hybrid system. The coding sequences of all the nine subunits of spinach chloroplast ATP synthase were cloned in two-hybrid vectors. The vectors were transformed into the yeast strains HF7c and SFY526 by various pairwise combinations, and the protein interactions were analyzed by measuring the yeast growth on minimal SD medium without serine, lucine and histidine. Interactions of γ Subunit with wild type or two truncated mutants of γ sununit, △εN21 and △εC45, which lose their abilities to inhibit the ATP hydrolysis, were also detected by in vitro and in vivo binding assay. The present results are largely accordant to the common structure model of F0F1-ATP synthase. Different from that in the E. Coli F0F1-ATP synthase, the δ subunit of chloroplast ATP syn- thase could interact with β,γ,ε and all the CF0 subunits in the two-hybrid system. These results suggested that though the chloroplast ATP synthase shares the similar structure and composition of subunits with the enzyme from E. Coli, it may be different in the subunit interactions and con- formational change during catalysis between these two sources of ATP synthase. Based on the present results and our knowledge of structure model of E. Coli ATP synthase, a deduced structure model of chloroplast ATP synthase was proposed.     

Hypoosmotic shock induces a stateⅠtransition of photosynthetic apparatus in Dunaliella salina

State transition has been considered as a short-term chromatic adaptation of photosynthetic apparatus in plants[1,2]. When photosystemⅡ(PSⅡ) is excited more than photosystem Ⅰ(PSⅠ) upon illumination, the inter-system electron carriers, such as plastoquinone (PQ) and cytochrome b6f complexes (Cyt b6f), are reduced, and a thylakoid membrane-bound protein kinase for light har-vesting chlorophyll-binding protein (LHCP) is activated, resulting in LHCP phosphorylation[3]. Upon phosphoryla-…     

H_∞ control for stochastic systems with time-delay

1.INTRODUCTION Physicalplantsareunavoidabletobeaffectedbydis turbance,time delayanduncertainty,whichmay makesomeunwantedinfluenceonthesystem’sper formanceandevenresultininstability.Howtoavoid andcounteractsuchdisadvantagesthroughfeedback designhasbeenaresearchtopicunderintensiveinves tigationrecently[1～7].Inpractice,twokindsofdisturbancesareoften encountered:stochastic(orrandom)disturbanceand deterministicdisturbance.Forthestochasticdistur bance,systemsunderconsiderationaremodeledand st…     

CM碰撞模型的建立及试验验证

为了再现交通事故 ,该文从间接描述碰撞阶段的特征参数出发 ,采用不同的参数子集 ,建立了分类碰撞模型。提出了虚拟模型的概念 ,应用人工智能技术 ,根据特定碰撞类型的特点进行分析 ,充分利用这些特点进行模型假设 ,简化了模型的求解。编制了计算机应用软件。并用日本汽车研究所与整车碰撞实验数据系列进行验证 ,结果表明本模型可以应用于事故再现     

GC-MS结合保留指数分析轮钟花根的挥发性成分

采用气相色谱-质谱技术(GC-MS)结合保留指数(RI)对不同方法提取的轮钟花根挥发性成分进行分析,结果表明：轮钟花根的挥发性成分以酸类、烃类、酯类和醇类为主,确定为76种化合物,其中,水蒸气蒸馏法、索式提取法和超声辅助萃取法各确定根中24,45,39种化合物,三种方法提取的质量分数最高的成分均为亚油酸.     

Controllability of General Linear Discrete Multi-Agent Systems with Directed and Weighted Signed Network

This paper investigates the controllability of general linear discrete-time multi-agent systems with directed and weighted signed networks by using graphic and algebraic methods. The nondelay and delay cases are considered respectively. For the case of no time delay, the upper bound condition of the controllable subspace is given by using the equitable partition method, and the influence of coefficient matrix selection of individual dynamics is illustrated. For the case of single delay and multi...     

MODIS在青藏高原大范围积雪制图中的应用及存在的问题

积雪是地球表面重要的组成部分之一,精确监测积雪覆盖及其动态变化是地球科学的一个重要研究方向。本文以我国主要积雪区之一的青藏高原作为研究区域,研究了MODIS数据在青藏高原大范围积雪制图中的应用。使用基于NDSI阈值法的积雪像元识别方法,对2002-2003年度青藏高原的积雪状况进行了监测。对监测结果的分析表明,虽然这种算法目前还存在一些不足,但对青藏高原大区域的积雪监测仍是一种极为有效的方法。