摘要：
Cry5Ba is a delta-endotoxin produced by Bacillus thuringiensis PS86A1 NRRL B-18900. It is active against nematodes and has great potential for nematode control. Here, we predict the first theoretical model of the three-dimensional (3D) structure of a Cry5Ba toxin by homology modeling on the structure of the Cry1Aa toxin, which is specific to Lepidopteran insects. Cry5Ba resembles the previously reported Cry1Aa toxin structure in that they share a common 3D structure with three domains, but there are some distinctions, with the main differences being located in the loops of domain I. Cry5Ba exhibits a changeable extending conformation structure, and this special structure may also be involved in pore-forming and specificity determination. A fuller understanding of the 3D structure will be helpful in the design of mutagenesis experiments aimed at improving toxicity, and lead to a deep understanding of the mechanism of action of nematicidal toxins.
摘要：
The interactions of meso-tetraphenylporphyrin (TPP), meso-tetraphenylporphyrin cobalt(II) (CoTPP) and protein in the presence of a cyclodextrin derivative, heptakis(2,6-di-O-n-octyl)-beta-cyclodextrin (Oc-beta-CD), have been investigated. In the presence of Oc-beta-CD, significant increase of TPP fluorescence was realized, but the increased fluorescence was quenched by CoTPP. To further investigate the fluorescence-quenched system and explore its potential application in bioanalysis, a strategy has been devised to restore the quenching fluorescence of TPP upon interacting with protein. The restoration of TPP fluorescence in the present system is fast and accomplished upon interaction with bovine serum albumin (BSA) or human serum albumin (HSA). On the basis of the spectroscopic measurement and excited state fluorescence lifetime, the mechanism of TPP fluorescence quenching is attributed to formation of a ground-state complex of TPP and CoTPP, and the fluorescence restoration is attributed to the binding of CoTPP with the protein molecule which destroys the aggregate, releasing the free base porphyrin. With optimized conditions, the calibration equations are linear from 0.80 to 75.4 mu g mL(-1) BSA and from 3.20 to 93.2 mu g mL(-1) HSA. The corresponding detection limits are 0.32 mu g mL(-1) for BSA and 1.06 mu g mL(-1) for HSA, respectively The method was used for the direct assay of HSA content in human serum. The result is comparable to that obtained by another method. The recovery from BSA in synthetic sample is also satisfactory.
作者机构：
[杨运泉; 罗和安; 段正康; 刘文英] College of Chemical Engineering, Xiangtan University, Xiangtan 411105, China;Department of Chemistry and Environmental Engineering, Hunan City University, Yiyang 413049, China;[Zeng Y.-L.] College of Chemical Engineering, Xiangtan University, Xiangtan 411105, China<&wdkj&>Department of Chemistry and Environmental Engineering, Hunan City University, Yiyang 413049, China
通讯机构：
College of Chemical Engineering, Xiangtan University, China
作者机构：
[李晓如; 邹桥; 谭斌斌; 李国辉] School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;[李国辉] Department of Chemistry and Environment Engineering, Hunan City College, Yiyang 413000, China
通讯机构：
School of Chemistry and Chemical Engineering, Central South University, China
摘要：
A new method for protein separation by the gold nanotubules membrane based on the immunoreaction between antibody and antigen was described. The gold nanotubules can be electrolessly plated within the pores of polycarbonate nanoporous filtration membranes. The capture antibody, bovine IgG, was modified onto the inner wall of An nanotubules by glutaraldehyde interlinking method. The transport behaviour of detecting antibody through the nanotubules modified with capture antibody was investigated. When the diameter of the nanotubule was much larger than the size of the antibodies, there was no obvious difference between the transport rates for the proteins studied here through nanotubules. When the diameter of the nanotubule was ca. 30 nm, the transport of the goat anti-cat antibody through the nanotubules membrane was slow. Compared with goat anti-cat IgG, goat anti-bovine antibody transported through nanotubules membrane faster due to the immunoreaction between goat anti-bovine antibody and bovine IgG modified onto the pores of the membrane and the separation efficiency was 5.6. The results indicated that the gold nanotubule membranes showed good separating capability for protein without the loss of activity of the antibodies. (c) 2007 Published by Elsevier B.V.
作者机构：
[兰正刚; 李国辉; 李晓如] School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;[李国辉] Department of Chemistry, Hunan City College, Yiyang 413000, China
通讯机构：
School of Chemistry and Chemical Engineering, Central South University, China
作者机构：
[袁艳; 胡拥军; 石西昌; 徐徽; 陈白珍] School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China;[胡拥军] Department of Chemistry, Hunan City University, Yiyang 413049, China
通讯机构：
School of Metallurgical Science and Engineering, Central South University, China
作者机构：
[Luo Xinxiang; Wen Ruiming] Department of Chemistry and Environmental Engineering, Hunan City University, Yiyang Hunan, China;[Qu Fanqi; Huang Xiaoling] College of Chemistry and Molecular Sciences, Wuhan University, Wuhan Hubei, China
通讯机构：
Department of Chemistry and Environmental Engineering, Hunan City University, China
摘要：
Four novel bridged dianilines containing fluorine were synthesized using 4-chloro-3, 5-dinitrobenzotrifluoride and diamine by two step condensation and reduction. The structures of corresponding compounds were determined by means of IR, NMR and elemental analysis.
作者机构：
上海师范大学生命与环境科学学院生物系遗传学实验室,上海,200234;湖南城市学院,化学与环境工程系,湖南,益阳,413000;[刘石泉] Department of Chemistry and Environment Engineering, Hunan City University, Yiyang 413000, China, Genetics Laboratory, Department of Biology, Shanghai Normal University, Shanghai 200234, China;[李小军; 余庆波; 周根余] Genetics Laboratory, Department of Biology, Shanghai Normal University, Shanghai 200234, China
通讯机构：
[Zhou, G.-Y.] G;Genetics Laboratory, , Shanghai 200234, China
作者机构：
[袁艳; 胡拥军; 陈白珍; 李义兵] School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China;[胡拥军] Department of Chemistry, Hunan City University, Yiyang 413049, China
通讯机构：
[Hu, Y.-J.] S;School of Metallurgical Science and Engineering, , Changsha 410083, China
作者机构：
[罗一鸣; 刘长辉; 唐瑞仁] School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;[刘长辉] Department of Chemistry and Environmental Engineering, Hunan City University, Yiyang 413029, China;[杨华武] The Technology Center, Changsha Cigarette Factory, Changsha 410014, China
通讯机构：
School of Chemistry and Chemical Engineering, Central South University, China
