Reactions of triethylphosphine gold(I) complexes with heme proteins: novel spin-state changes in cytochrome b562, myoglobin, and hemoglobin

Effects of gold(I) antiarthritic drugs and related compounds on Pseudomonas putida

The effects of the antiarthritic drugs aurothiomalate (AuTm), aurothioglucose (AuTg), auranofin, its metabolite triethylphosphinegold(I)thioglucose (Et3PAuTg), and several related complexes on the growth of Pseudomonas putida were studied. Two strains were used, one of which (BK135) was more sensitive to Et3PAuTg (tolerant up to 4 microM) than the other (BK403; tolerant to at least 500 microM). Gold thiolate complexes and thiolate ligands alone had little effect on growth. Gold phosphine complexes increased the length of the lag phase of growth and reduced oxygen uptake. Marked changes in cellular morphology were determined by electron microscopy. Copper(II) compounds and aurothiomalate were synergistic in their growth inhibitory effects towards these bacteria. Experiments with 195Au suggested that a mechanism does not exist for the short term (minutes) uptake of gold by sensitive or resistant bacteria, but the resistant strain appeared to limit gold uptake over a longer term (hours).

Localization of a new alpha-actinin binding site in the COOH-terminal part of actin sequence

The interaction of filamentous actin with alpha-actinin, an actin cross-linking protein, is well established. On the other hand, monomeric actin-alpha-actinin interaction has been a subject of controversy. In this report, we have characterized the interaction of monomeric actin, coated on plastic plates under conditions of non-polymerization, with alpha-actinin in presence of magnesium. Using specific polyclonal anti-actin antibodies, with the whole molecule or purified peptides, we have localized two sites of interaction on action molecule: one near Thr-103 and a new one in the twenty last amino acids.

Control of oxidative damage in rheumatoid arthritis by gold(I)-thiolate drugs

The roles of anti-arthritic gold(I)-thiolate drugs such as disodium aurothiomalate ('Myocrisin') in the modulation or promotion of oxygen radical-mediated oxidative damage in vivo are reviewed. In particular, the precise molecular mechanisms by which these novel second-line agents exert their therapeutic effects are discussed in terms of (i) the direct and indirect control of enzymes involved in the generation or scavenging of reactive oxygen species (ROS) such as superoxide ion, hydrogen peroxide and hydroxyl radical, (ii) the protection of proteins and relevant enzyme systems against attack by ROS and (iii) their direct involvement in the production (at appropriate 'target' sites) or scavenging of ROS in vivo. In addition, the role of the orally-effective gold(I)-phosphine complex auranofin in the control of oxidative damage in rheumatoid arthritis is also discussed.

Antigenic probes locate a serum-gelsolin-interaction site on the C-terminal part of actin

The implication of part of the C-terminal of actin (within the 285-375 sequence) in the interaction of serum gelsolin was investigated by the use of specific antibodies. These antibodies were directed against two or three discrete epitopes, one of which was specific for skeletal-muscle actin. Some of these epitopes were found to be near the serum gelsolin-actin interface. Thus it can be assumed that part of the C-terminal of actin is exposed at the barbed end of the actin filament. The interaction between tropomyosin and actin was also studied.