关于小分子热休克蛋白Hsp16.3各功能区作用的初步研究

小分子热休克蛋白Hsp16.3是一种存在于结核杆菌中的重要抗原,具有小分子热休克蛋白家族成员典型的3个功能区:N端疏水区,α-crystallin域和C端较短的非保守区.为了进一步研究其各功能区的作用,我们定义了Hsp16.3的3个功能区并在大肠杆菌中分别克隆、表达和纯化了N端区或C端区缺失的两个Hsp16.3残体蛋白.远紫外和近紫外圆二色谱分析结果显示,残体蛋白表现出与野生型蛋白相似的二级和三级结构.在九聚体野生型蛋白进行亚基重组装时,C端缺失的Hsp16.3残体蛋白能与野生型蛋白发生相互作用,形成异源寡聚体.在对野生型蛋白进行胰酶消化时,Hsp16.3的α-crystallin域对胰酶的消化具有抵抗能力.所有这些结果显示:在Hsp16.3的3个功能区中,α-crystallin域是一个相对独立和稳定的结构单元,它对该蛋白各级结构的维持十分重要.     

前言:分子机器专刊

<正>“分子机器”是由多个分子尺度的单元通过机械互锁构成的动态功能分子,其动态可控特性可调控各级尺度下物质功能并创造新物质. 2016年诺贝尔化学奖授予了让-皮埃尔·索维奇(Jean-Pierre Sauvage)、J.弗雷泽·斯托达特(Sir J. Fraser Stoddart)和伯纳德·L·费林加(Bernard L. Feringa)三位科学家,以表彰其设计并建造了最小的机器——“分子机器”.     

二价铜离子对牛正常朊蛋白二级结构的影响

研究了二价铜离子对牛朊蛋白的二级结构的影响.牛朊蛋白(BoPrPc)的小分子(BoPrPcS)和大分子(BoPrPcL)经初步纯化后,在含Cu2+的碱性溶液中氧化,用反相柱进行氧化态和还原态的BoPrPcL和BoPrPcS的分离.质谱分析证明氧化态的Bo-prPcL和BoPrPcS分子质量分别为24.064,15.819ku.用远紫外圆二色谱(Far-UVCD)分析显示,BoPrPcS在208和222m处出现两个负峰,为典型的α-螺旋型结构;而Bo-PrPcL在222nm处负峰减小.与未经氧化的BoPrPcL的质谱和CD结果比较后发现,氧化后的BoPrPcL在八肽重复区结合了6个Cu2+,其β-折叠含量明显增加.而Cu2+对BoPrPcS二级结构基本无影响.BoPrPcL结合Cu2+的特性及其二级结构的相应变化可能与细胞内抗Cu2+毒性与氧化压力有关.     

丹参缩酮内酯(丹参晶IX)的晶体及分子结构研究

题目所指化合物是从丹参中提取的一种天然化合物。分子式为C_(17)H_(16)O_3,分子量268.11,晶体空间群P2_12_12_1,晶胞参数a=25.931A,b=7.622A,c=6.770A晶胞中含4个分子。由MULTAN—78程序解出粗结构,经块对角矩阵最小二乘修正,偏离因子R为0.0643。本文对该化合物的晶体及分子结构进行了讨论,证实了缩酮内酯这样一种天然产物的新颖结构类型的存在。     

SYNTHESES AND PROPERTIES OF ELEVEN-COORDINATED COMPLEXES FORMED FROM LANTHANIDE NITRATES AND 1,8-NAPHTHO-16-CROWN-5

Complexs formed from lanthanide nitrates Ln (NO_3)_3 (Ln=La, Ce, Pr, Nd) and 1, 8-naph-tho-161crown-5 with a 1:1 stoichiometry have been synthesized and characterized by elementalanalyses; IR spectra, X-ray powder diagrams as well as thermogravimetric and differentialthermal analyses. A single crystal X-ray structural analysis indicates that the coordination num-ber of these complexes is eleven.     

MOLECULAR STRUCTURE AND ABSOLUTE CONFIGURATION OF THE DITERPENE LACTONE, PRAELOLIDE

Praelolide is a new compound which was isolated out from the gorgonian, Menella praelonga (Ridley), collected from the South Sea of China at Zhanjiang, Guangdong. The molecular formula is C_(28) H_(35) O_(12)C1. The research result by X-ray diffraction method on the crystal structure is presented. The compound is orthorhombic with space group P2_12_12, cell dimensions α=16.936, b=16.709, c=10.333, and Z=4. The structure has been solved by direct method and refined to R=0.055 for 2257 unique observable reflexions by least-squares. The molecule is composed of the major conformational isomer in which the three main rings(a six-membered ring, an eight-membered ring, a six-membered ring) take separately the form of chair-chairboat-chair, a five-membered actone ring, a C1 substitution, 4 acetate groups, and a three-membered epoxide ring. The absolute configuration of the molecule has also been determined by statistics (R factor ratio =1.012) and Bijvoet pairs observation. For 30 pairs of the greatest anomalo     

脱氢延胡索碱氯合物的分子结构和晶体结构

本文证明生物碱脱氢延胡索碱(Dehydrocrydaline)氯合物(C_(22)H_(24)NO_4HCl)的晶体属正交晶系,空间群:D_(2h)~(14)—P_(bcn),晶胞参数:a=8.52_6A,b=23.31_7A,c=24.79_8A,单位晶胞中分子数:z=8.用直接法导出全部非氢原子位置,经最小二乘法修正和差值Fourier逼近发现晶体中每个不对称单位内存在4.5个具有不同占有率的水分子.进一步修正后,最终偏离因子R=0.053. 晶体中的水分子以氯离子为中心缔合成颇为庞杂的水网结构. 文中对脱氢延胡索碱分子的结构特点和水网结构以及两部分结构的关系进行了讨论。     

利用物种的蛋白质系统发生图谱研究物种进化

随着后基因组时代的到来,越来越多的物种基因组序列被测定出来.基因组信息的大量增加,使得从基因组的水平研究物种进化成为可能.文中定义了物种的蛋白质系统发生图谱的概念,将之用于进化分析,并从蛋白质组的水平研究了物种间的进化关系.此方法与目前较流行的分子进化方法相比,具有适用范围广,结果稳定等特点.随着基因组测序工作的迅速发展,用蛋白质系统发生图谱构建进化树的方法将有很大的发展空间.     

A Statistical Analysis of Protein—Protein Interaction with Knowledge—Based Potential at Residue Level

Protein-protein recognition is an important step in biological processes, which still largely remains elusive. The inter-residue contact potential, CPij, describes the propensity of contact between two types of residue. In this study, several different CPij variants were examined with the objective of discriminating the binding potential of surface pairs. Using solvent mediated inter-molecule contact potential (SM-IMCPij), an evaluation model was deduced and tested. Using the evaluation model it was found that the SM-IMCPij gives a better performance than either residue mediated IMCPij(RM-IMCPij) or folding-residue contact potential (FCPij). The results suggest that the evaluation model provides a fast, effective, and discriminative method for the evaluation of proposed binding interfaces.