Identification of amino acid residues at nucleotide-binding sites of chaperonin GroEL/GroES and cpn10 by photoaffinity labeling with 2-azido-adenosine 5'-triphosphate

Although the chaperonin GroEL/GroES complex binds and hydrolyzes ATP, its structure is unlike other known ATPases. In order to better characterize its nucleotide binding sites, we have photolabeled the complex with the affinity analog 2-azido-ATP. Three residues of GroEL, Pro137, Cys138 and Thr468, are labeled by the probe. The location of these residues in the GroEL crystal structure [Braig, K., Otwinowski, Z., Hedge, R., Boisvert, D., Joachimiak, A., Horwich, A. & Sigler, P. (1994) Nature 371, 578-586: Boisvert, D. C., Wang, J., Otwinowski, Z., Horwich, A. L. & Sigler, P. B. (1996) Nat. Struct. Biol. 3, 170-177] suggests that 2-azido-ATP binds to an alternative conformer of GroEL in the presence of GroES. The labeled site appears to be located at the GroEL/GroEL subunit interface since modification of Pro137 and Cys138 is most readily explained by attack of a probe molecule bound to the adjacent GroEL subunit. Labeling of the co-chaperonin, GroES, is clearly demonstrated on gels and the covalent tethering of nucleotide allows detection of a GroES dimer in the presence of SDS. However, no stable peptide derivative of GroES could be purified for sequencing. In contrast, the GroES homolog, yeast cpn10, does give a stable derivative. The modified amino acid is identified as the conserved Pro13, which corresponds to Pro5 in Escherichia coli GroES.     

User-Centric Identity Management: New Trends in Standardization and Regulation

In offering services to individuals, enterprises often deal with a lot of personal information, the improper handling of which creates security risks for both the enterprises and individuals concerned. Authentication procedures usually assume specific behavior on the part of individuals, and this perception becomes a critical part of an enterprise's security mechanism. Identity management systems are touted as a solution, but even though users and enterprises are stakeholders in the broader conversation about identity management, their interests aren't necessarily aligned: who's in control, and whose interests will prevail in ease of conflict? The European Commission-funded Privacy and Identity Management tor Europe project (Prime: www.prime-projeet.eu) proposes a solution driven by the EU Privacy Directive (95/46/EC; http://ec.europa.eu/justice_home/fsj/privacy/law/), which puts the user in control wherever possible. This article focuses on that project and how it interacts with standardization initiatives and international organizations.     

Stromal degradation by the malignant epithelium in pancreatic cancer and the therapeutic potential of proteolytic inhibition

off matrix metalloproteinases (MMPs) and the tissue inhibitors of the metalloproteinases (TIMPs) are described and reviewed. The role of the MMPs and their inhibitors in tumour invasion and metastasis is reviewed and the interaction between the extracellular matrix and these enzymes is discussed. The expression and activity of the MMPs and TIMPs in pancreatic cancer is reported with reference to the literature and the author's own work. The effect of MMP inhibitors (MMPIs) in vivo and the use of batimastat and marimastat (both; British Biotech Pharmaceuticals, Oxford, UK) in animal experiments are also described. Preliminary phase II and III clinical trial data of marimastat in advanced pancreatic cancer is reported.     

The uptake and translocation of malathion by the stored wheat grain

Malathion residues are found chiefly in regions of high lipid content in the individual wheat grain; mainly in the germ and scutellum, and seldom in the starchy endosperm. Malathion applied directly to the endosperm is rapidly transported to other regions. This has been established using gas-liquid chromatography, and also using radioactively labelled malathion.Some grains have an enhanced affinity for malathion, and this property is not related to the size or weight of the grain. The current methods for calculating and applying safe limits for pesticide residual levels in grain are criticised in the light of these results.Some aspects of how Sitophilus granarius larvae, living within the wheat grain, are affected by externally applied malathion are also considered.     

The development of professional skills using a product developmentscenario

Personal and professional development is now recognised as an important feature in the education of an engineer. The paper describes a scenario based on a `ghost company' that has been successfully used to develop these skills in students. It involves team working between two geographically remote sites using such techniques as video conferencing, e-mail and the Internet. Evaluation of the work has taken place and the results are presented with suggestions for further work