Structure of a C-type mannose-binding protein complexed with an oligosaccharide.

C-type (Ca(2+)-dependent) animal lectins such as mannose-binding proteins mediate many cell-surface carbohydrate-recognition events. The crystal structure at 1.7 A resolution of the carbohydrate-recognition domain of rat mannose-binding protein complexed with an oligomannose asparaginyl-oligosaccharide reveals that Ca2+ forms coordination bonds with the carbohydrate ligand. Carbohydrate specificity is determined by a network of coordination and hydrogen bonds that stabilizes the ternary complex of protein, Ca2+ and sugar. Two branches of the oligosaccharide crosslink neighbouring carbohydrate-recognition domains in the crystal, enabling multivalent binding to a single oligosaccharide chain to be visualized directly.     

A novel calcium binding site in the galactose-binding protein of bacterial transport and chemotaxis

The refined 1.9-A resolution structure of the periplasmic D-galactose-binding protein (GBP) reveals a calcium ion surrounded by seven ligands, all protein oxygen atoms. A nine-residue loop (amino-acid positions 134-142), which is preceded by a beta-turn and followed by a beta-strand, provides five ligands from every second residue. The last two ligands are supplied by the carboxylate group of Glu 205. The entire GBP Ca2+-binding site adopts a conformation very similar to the site in the 'helix-loop-helix' or 'EF-hand' unit commonly found in intracellular calcium-binding proteins, but without the two helices. Structural analyses have also uncovered the sugar-binding site some 30 A from the calcium and a site for interacting with the membrane-bound trg chemotactic signal transducer approximately 45 A from the calcium. Our results show that a common tight calcium binding site of ancient origin can be tethered to different secondary structures. They also provide the first demonstration of a metal-binding site in a protein which is involved in bacterial active transport and chemotaxis.     

射流侵彻复合靶的工程计算方法

采用遂次逼近法建立了射流侵彻有限厚度靶的工程计算公式，进而提出了射流侵彻复合靶的工程计算方法。计算结果与实测值符合较好。可用补破甲弹和复合靶的设计计算。     

Microtubule-motor activity of a yeast centromere-binding protein complex.

During cell division, sister chromosomes segregate from each other on a microtubule-based structure called the mitotic spindle. Proteins bind to the centromere, a region of chromosomal DNA, to form the kinetochore, which mediates chromosome attachment to the mitotic spindle microtubules. In the budding yeast Saccharomyces cerevisiae, genetic analysis has shown that the 28-basepair (bp) CDEIII region of the 125-bp centromere DNA sequence (CEN sequence) is the main region controlling chromosome segregation in vivo. Therefore it is likely that proteins binding to the CDEIII region link the centromeres to the microtubules during mitosis. A complex of proteins (CBF3) that binds specifically to the CDEIII DNA sequence has been isolated by affinity chromatography. Here we describe kinetochore function in vitro. The CBF3 complex can link DNA to microtubules, and the complex contains a minus-end-directed microtubule-based motor. We suggest that microtubule-based motors form the fundamental link between microtubules and chromosomes at mitosis.     

工科化工原理实验教学改革的探索

在化工原理实验教学中,就课程内容的选择,实验理论课的讲解,电化教学手段的采用,实验成绩的考核办法,实验指导方式的改革等方面作了一些探索性工作.     

路基工程施工探讨

从路基填筑前原地面的处理、路基填料的选择和填土路基的压实等方面全面总结了路基工程的施工经验。     

地下工程测量技术探讨

随着各种大型地下工程建设的实施,矿山测量演化为地下工程测量。从地下工程对测量技术的4项要求入手,分析了近些年地下工程测量仪器的发展,并从4个方向对地下工程测量技术的发展做了展望。     

Identification of a receptor for protein import into mitochondria

Anti-idiotypic antibodies, prepared using a chemically synthesized signal peptide of a mitochondrial precursor protein, recognized a mitochondrial integral membrane protein (p32). Fab fragments derived from both anti-idiotypic antibodies and monospecific antibodies against purified p32 inhibited protein import into mitochondria. Moreover, anti-p32 antibodies specifically immunoprecipitated a precursor-p32 complex after detergent solubilization of mitochondria. Immunoelectron microscopy and subfractionation of mitochondria indicate that p32 is located in contact sites between the outer and inner mitochondrial membranes.     

射流侵彻陶瓷靶试验研究与工程计算模型

该文介绍了射流侵彻陶瓷靶的系统试验研究，全面地分析了射流侵彻陶瓷靶的规律和陶瓷靶抗射流侵彻机理，通过分析射流着靶速度和破甲速度的关系曲线，建立了射流着靶速度与破甲速度的力学模型和工程计算模型，提出了射流侵彻陶瓷靶的工程计算模型和陶瓷靶对断裂射流的干扰因子。     

Infective transmission and characterisation of a C-type virus released by cultured human myeloid leukaemia cells.

A C-type virus isolated from long term cultures of myeloid cells from a patient with acute myelogenous leukaemia is infectious for a wide variety of cells. The establishment of chronically infected cells enabled us to characterise the virus by biological, immunological, and biochemical tests. The virus is closely related to the simian sarcoma-associated virus isolated from a woolly monkey fibrosarcoma.     

网吧群无线接入网络工程

采用无线方式将网吧群接入互联网 ,解决了无线接入的稳定性、安全性等问题 ,同时 ,也大大地降低了运营成本。     

《植物细胞工程》课程探索与改革

从理论教学和实验教学两方面对《植物细胞工程》课程进行探索与改革,以提高教学质量及培养学生创新能力,从而满足当今社会人才的需求.     

建筑工程设计监理初探

介绍了设计监理的特点和设计监理过程中监理工程师的主要任务，阐述了建立设汁监理在建筑工程中的必要性，详述了设计监理的内容、设计阶段监理工程师的监理方法、设计监理过程中常见的设计问题及控制方法。     

《工程力学》的教学实践与探索

结合《工程力学》的课程特点,运用一些灵活、生动、有趣的教学方法,能收到较好的教学效果。如:学生动手,教师提问,提高学生的学习兴趣;恰当比喻,适时举例,促进学生对抽象理论的理解;及时归纳整理,帮助学生牢固掌握专业知识;结合运用多媒体辅助教学,提高教学效果。