Excitation-contraction coupling in skeletal muscle involves conformational coupling between dihydropyridine receptors (DHPRs) in the plasma membrane and ryanodine receptors (RyRs) in the sarcoplasmic reticulum. However, it remains uncertain what regions, if any, of the two proteins interact with one another. Toward this end, it would be valuable to know the spatial interrelationships of DHPRs a...

The energetics of weak interactions (van der Waals forces, hydrogen bonding) are difficult to quantify in biological ligand-receptor pairs. Insight into the biochemical role these forces play is critical to an understanding of signal transduction events and the drug discovery process. Ruthenium pentaammine and iron tetracyano complexes modified with either biotin or desthiobiotin have been synt...

Enzymatic and homogeneous catalysis offer complementary means to produce enantiopure products. Incorporation of achiral, biotinylated aminodiphosphine-rhodium complexes in (strept)avidin affords enantioselective hydrogenation catalysts. A combined chemogenetic procedure allows the optimization of the activity and the selectivity of such artificial metalloenzymes: the reduction of acetamidoacryl...

The main biochemical function of biotin, one of the B complex group of vitamins, is as a coenzyme in certain enzymatic reactions associated with decarboxylation and carbon dioxide fixation. It thus has an important role in intermediary metabolism (1). Biotin is so widely distributed in foods and so abundantly produced by intestinal bacteria that it is doubtful whether a spontaneous biotin defic...

Applicability of in vitro biotinylated ubiquitin for evaluation of endogenous ubiquitin conjugation and analysis of ubiquitin-associated protein-protein interactions has been investigated. Incubation of rat brain mitochondria with biotinylated ubiquitin followed by affinity chromatography on avidin-agarose, intensive washing, tryptic digestion of proteins bound to the affinity sorbent and their...

To expand the applicability of the biotin-(strept)avidin system, a biotin analog with reversible binding under non-denaturing conditions has been designed, and its applications in protein labeling, detection, and isolation have been evaluated.

Variations in egg size and composition can have important consequences for the quality of offspring. We investigated the effect of temperature, in the 5 days preceding laying, on yolk, albumen, shell and total egg mass. Moreover, we examined the influence of temperature on three important egg components, i.e. the yolk carotenoids and the albumen lysozyme and avidin. In our experimental conditio...

Biotin-binding proteins (BBPs), such as avidin and streptavidin, represent potent insect control compounds which could be delivered via transgenic plants. The effects of BBPs on some pasture pests were determined. Black field cricket nymphs (Teleogryllus commodus) had significantly reduced growth and survival when fed on lettuce leaves painted with purified avidin. Adult clover root weevils (Si...

Noncovalent attachment of avidin to the membrane of prebiotinylated red blood cells (RBCs) induces lysis via the alternative pathway of complement (APC). Lysis is not species-dependent; RBCs from humans, rabbits, rats, and sheep were lysed with both autologous and all heterologous sera. Both biotinylated and native cells were not lysed. Lysis was observed at an avidin surface density of about 1...

Tumor imaging with labeled liposomes is slow; although they reach the tumor quickly, their blood clearance is slow, and the high blood background hinders early imaging. We have developed a rapid tumor imaging technique based on the active removal of liposomes from the circulation by using the avidin-biotin system. 67Ga- or 111In-labeled liposomes with biotin molecules bound on the surface were ...