Small heat shock proteins function in a chaperonelike manner to prevent the precipitation of proteins under conditions of stress (e.g. heat). ␣-Crystallin, the major mammalian lens protein, is a small heat shock protein. The mechanism of chaperone action of these proteins is poorly understood. In this paper, the conformational state of a protein when it forms a high molecular weight complex with ␣-crystallin is investigated by examining, using NMR spectroscopy and size exclusion high performance liquid chromatography, the interaction of ␣-crystallin with ␣-lactalbumin and its various intermediately folded (molten globule) states. The complex is formed following reduction of ␣-lactalbumin by dithiothreitol in the presence of ␣-crystallin, and this interaction has been monitored in real time by 1 H NMR spectroscopy. It is concluded that ␣-crystallin interacts with a disordered molten globule state of ␣-lactalbumin while it is on an irreversible pathway toward aggregation and precipitation. ␣-Crystallin does not interact, however, with molten globule states of ␣-lactalbumin that are stable in solution, e.g. the reduced and carboxyamidated species. It is proposed that ␣-crystallin distinguishes between the various molten globule states of ␣-lactalbumin on the basis of the lifetimes of these states, i.e. the protein must be in a disordered molten globule state for a significant length of time and on the pathway to aggregation and precipitation for interaction to occur.

A comprehensive contemporary cycle for stocks and flows of copper is characterized and presented, incorporating information on extraction, processing, fabrication and manufacturing, use, discard, recycling, final disposal, and dissipation. The analysis is performed on an annual basis, ca. 1994, at three discrete governmental unit levels−56 countries or country groups that together comprise essentially all global anthropogenic copper stocks and flows, nine world regions, and the planet as a whole. Cycles for all of these are presented and discussed, and a “best estimate” global copper cycle is constructed to resolve aggregation discrepancies. Among the most interesting results are (1) transformation rates and recycling rates in apparently similar national economies differ by factors of two or more (country level); (2) the discard flows that have the greatest potential for copper recycling are those with low magnitude flows but high copper concentrationselectronics, electrical equipment, and vehicles (regional level); (3) worldwide, about 53% of the copper that was discarded in various forms was recovered and reused or recycled (global level); (4) the highest rate of transfer of discarded copper to repositories is into landfills, but the annual amount of copper deposited in mine tailings is nearly as high (global level); and (5) nearly 30% of copper mining occurred merely to replace copper that was discarded. The results provide a framework for similar studies of other anthropogenic resource cycles as well as a basis for supplementary studies in resource stocks, industrial resource utilization, waste management, industrial economics, and environmental impacts.

Affinity depletion of abundant proteins from human plasma has become a routine sample preparation strategy in proteomics used prior to protein identification and quantitation. To date, there have been limited published studies comparing the performance of commercially available depletion products. We conducted a thorough evaluation of six depletion columns using 2-DE combined with sophisticated image analysis software, examining the following criteria: (i) efficiency of high-abundance protein depletion, (ii) non-specific removal of other than the targeted proteins and (iii) total number of protein spots detected on the gels following depletion. From all the products investigated, the Seppro IgY system provided the best results. It displayed the greatest number of protein spots on the depleted plasma gels, minimal non-specific binding and high efficiency of abundant protein removal. Nevertheless, the increase in the number of detected spots compared with the second best performing and cheaper multiple affinity removal column (MARC) was not shown to be statistically significant. The ProteoPrep spin column, considered to be the ''deepest'' depletion technique available at the time of conducting the study, surprisingly displayed significantly fewer spots on the flow-through fraction gels compared with both the Seppro and the MARC. The spin column format and low plasma capacity were also found to be impractical for 2-DE. To conclude, we succeeded in providing an overview of the depletion columns performances with regard to the three examined areas. Our study will serve as a reference to other scientists when deciding on the optimal product for their particular projects.

The small heat-shock protein, A-crystallin, has chaperone ability whereby it stabilises proteins under stress conditions. In this study, alterations in the structure of A-crystallin during its interaction with a variety of substrate proteins (insulin, A-lactalbumin, ovotransferrin and serum albumin) under stress conditions have been examined using visible absorption, 31 P-NMR and 1 H-NMR and fluorescence spectroscopy. The fluorescence and 31 P-NMR data imply that during the chaperone action of A-crystallin under reducing conditions, there is a slight increase in hydrophilicity of its N-terminal region and an alteration in flexibility of its C-terminal region, but overall, A-crystallin does not undergo a gross structural change. The fluorescence data suggest that substrate proteins interact with A-crystallin in a molten globule or intermediately folded state. The same conclusion is made from 1 H-NMR spectroscopic monitoring of the interaction of A-crystallin with substrate proteins, e.g. the insulin B chain. The stoichiometry of interaction between A-crystallin and the various substrate proteins reveals that steric factors are important in determining the efficiency of interaction between the two proteins, i.e. on a molar subunit basis, A-crystallin is a more efficient chaperone protein with smaller substrate proteins. Comparison is also made between the high-molecular-mass (HMM) complexes formed between A-crystallin and ovotransferrin when reduced and heat stressed. Under heating conditions, fluorescence spectroscopy indicates that the HMM complex has a greater exposure of hydrophobicity to solution than that formed by reduction. Furthermore, in interacting with heated ovotransferrin, the C-terminal extension of the AB-crystallin subunit preferentially loses its flexibility suggesting that it is involved in stabilising bound ovotransferrin. By contrast, this extension is only partially reduced in flexibility in the HMM complex formed after reduction of ovotransferrin. The functional role of the C-terminal extensions in the chaperone action and the overall quaternary structure of A-crystallin is discussed.

Purpose There is no clear guidance for responsible food service operations to reduce their environmental footprint, so the efforts put forth by a restaurant may not have the environmental impact intended. As a result, Green Seal conducted life cycle assessment research on restaurants and food service operations to define priorities for environmental improvement. This information was then used to develop a sustainability standard and certification (i.e., ecolabel) program.Methods The life cycle assessment study focused on the day-to-day activities of running a restaurant, including direct and indirect contributions. To do this, a restaurant and food service operations model was developed by grouping the operational activities into four subsystems: food procurement, food storage, food preparation and cooking, and service/support. Data was collected from a range of restaurants in the United States. The impact categories examined included respiratory inorganics, acidification/eutrophication, fossil fuels, ecotoxicity, carcinogens, land use, and climate change.