Activation of the 20S proteasome of Xenopus oocytes by cardiolipin: blockage of the activation of trypsin-like activity by the substrate

Posttranslational protein modifications by reactive nitrogen and chlorine species and strategies for their prevention and elimination

Proteins are subject to various posttranslational modifications, some of them being undesired from the point of view of metabolic efficiency. Prevention of such modifications is expected to provide new means of therapy of diseases and decelerate the process of aging. In this review, modifications of proteins by reactive nitrogen species and reactive halogen species, is briefly presented and means of prevention of these modifications and their sequelae are discussed, including the denitrase activity and inhibitors of myeloperoxidase.

Atomic force microscopy studies of interaction of the 20S proteasome with supported lipid bilayers

The 20S proteasome plays important roles in degradation of intracellular proteins. Mechanisms of its activation, its localization in cells, and its binding to biomembranes are not well understood. In this study, we used atomic force microscopy (AFM) to investigate interactions between the 20S proteasome and supported bilayers of various lipids in a buffer. We found that the 20S proteasome specifically bound to supported bilayers containing phosphatidylinositol (PI), but did not bind to supported bilayers containing phosphatidylcholine, phosphatidic acid or dioleoyltrimethylammonium propane. Binding of the 20S proteasomes had a high orientation; almost all were in a top view position. The specific and orientational binding of the 20S proteasome with PI may play important roles inside cells such as endoplasmic reticulum (ER) membrane. Use of AFM to study supported bilayers provides new information on ligand-receptor interactions.