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排序方式: 共有606条查询结果,搜索用时 687 毫秒
601.
602.
Haruki Yamamoto Jiro Nomata Yuichi Fuita 《Photochemical & photobiological sciences》2008,7(10):1238-1242
Dark-operative protochlorophyllide oxidoreductase (DPOR) is a nitrogenase-like enzyme catalyzing D-ring reduction of protochlorophyllide in chlorophyll and bacteriochlorophyll biosynthesis. DPOR consists of two components, L-protein and NB-protein, which are structurally related to nitrogenase Fe-protein and MoFe-protein, respectively. Neither Fe-protein nor MoFe-protein is expressed as an active form in Escherichia coli due to the requirement of many Nif proteins for the assembly of the metallocenter and the maturation specific for diazotrophs. Here we report the functional expression of DPOR components from Rhodobacter capsulatus in Escherichia coli. Two overexpression plasmids for L-protein and NB-protein were constructed. L-protein and NB-protein purified from E. coli showed spectroscopic properties similar to those purified from R. capsulatus. L-protein and NB-protein activities were evaluated using a crude extract of E. coli overexpressing NB-protein and L-protein, respectively. Specific activities of the purified L-protein and NB-protein were 219+/-38 and 52.8+/-5.5 nmolChlorophyllide min(-1) mg(-1), respectively, which were even higher than those of L-protein and NB-protein purified from R. capsulatus. These E. coli strains provide a promising system for structural and kinetic analyses of the nitrogenase-like enzymes. 相似文献
603.
Shuchismita Dutta Kyle Burkhardt Jasmine Young Ganesh J. Swaminathan Takanori Matsuura Kim Henrick Haruki Nakamura Helen M. Berman 《Molecular biotechnology》2009,42(1):1-13
The Protein Data Bank (PDB) is the repository for three-dimensional structures of biological macromolecules, determined by
experimental methods. The data in the archive is free and easily available via the Internet from any of the worldwide centers
managing this global archive. These data are used by scientists, researchers, bioinformatics specialists, educators, students,
and general audiences to understand biological phenomenon at a molecular level. Analysis of this structural data also inspires
and facilitates new discoveries in science. This chapter describes the tools and methods currently used for deposition, processing,
and release of data in the PDB. References to future enhancements are also included.
Shuchismita Dutta, Kyle Burkhardt, and Ganesh J. Swaminathan have contributed equally to this work. 相似文献
604.
605.
Naosuke Kojima M. Sato Katsuyuki Imai Mitsutaka Miura Yoshikazu Matano Haruki Senoo 《Histochemistry and cell biology》1998,110(2):121-128
When cultured on a polystyrene surface or aminoalkylsilane-coated cover glasses, rat and human hepatic stellate cells exhibit
a flattened, fibroblast-like shape with well-developed stress fibers. However, culturing the cells on type I collagen gel
results in the elongation of long, multipolar cellular processes, whereas cells cultured on Matrigel maintain their round
shapes. Dual fluorescence staining of microtubules and fibrillar actin indicated that the processes extend together with collagen
fibers and contained microtubules as the core, whereas the periphery contained fibrillar actin. Immunofluorescence staining
of vinculin showed that the focal adhesions were distributed mainly in lamellipodia when cultured on aminoalkylsilane-coated
cover glasses, whereas in the cells cultured on type I collagen gel they were localized to the tips of the processes and along
their bottom surface contacting collagen fibers. Wortmannin, as well as staurosporin and herbimycin A, inhibited the elongation
process and induced the retraction of elongated processes. The wortmannin treatment also resulted in an alteration in focal
adhesion distribution from the processes to cell bodies. These results indicate that the cell surface integrin binding to
interstitial collagen fibers induces the elongation of processes through signaling events and the subsequent cytoskeleton
assembly in hepatic stellate cells.
Accepted: 12 February 1998 相似文献
606.
Pattern of shedding of small, round-structured virus particles in stools of patients of outbreaks of food-poisoning from raw oysters 总被引:4,自引:0,他引:4
The pattern of shedding of the small, round-structured virus (SRSV) particles in the stools of patients who suffered from food-poisoning due to raw oysters was investigated. The duration and concentration of fecal shedding of the SRSV particles were studied by electron microscopic examinations of stool specimens obtained during the course of illness to see a relation of viral shedding to day of illness. It was found that the fecal shedding of the SRSV particles occurred within five days of illness; thereafter, the concentration of the SRSV particles in feces rapidly decreased within a few days during the course of illness. 相似文献