Point mutations in either of the two nucleotide-binding domains (NBD) of Hsp104 (NBD1 and NBD2) eliminate its thermotolerance function in vivo. In vitro, NBD1 mutations virtually eliminate ATP hydrolysis with little effect on hexamerization; analogous NBD2 mutations reduce ATPase activity and severely impair hexamerization. We report that high protein concentrations overcome the assembly defect...

The ability of silicon to dissolve in physiological environments allows its use as the basis of a highperformance inorganic integrated circuit technology for active, bioresorbable implant devices. N. R. Aluru, J. A. Rogers, and co-workers perform systematic experimental and theoretical studies of hydrolysis of silicon nanomembranes at near neutral pH, as described on page 1857. This image shows...

The conditions for optimal rates of ATP hydrolysis catalyzed by the chloroplast ATP-synthase (A TPase), CFoF,, after isolation and reconstitution into asolectin liposomes have been investi­ gated. The rate of ATP hydrolysis was measured either after oxidation of CF0F, (by incubation with iodosobenzoate) or after reduction of CFoF, (by incubation with dithiothreitol). In both cases a rate of abo...

Biomolecular machines fulfill their function through large conformational changes that typically occur on the millisecond time scale or longer. Conventional atomistic simulations can only reach microseconds at the moment. Here, extending the minimalist model developed for protein folding, we propose the "switching Gō model" and use it to simulate the rotary motion of ATP-driven molecular motor ...

Laser Raman spectroscopy has been used to examine the conformations of the protein and phospholipid components of sarcoplasmic reticulum from rabbit white skeletal muscle. The phospholipid component is shown to have the conformation of fluid, liquid-crystalline lipids, even at 10 degrees C, and no breaks in the lipid conformation are observed in the range of 10-37 degrees C. Protein (predominan...

Formation of D-loops during the exchange of strands between a circular single-stranded DNA and a completely homologous linear duplex proceeds optimally when the duplex DNA is added to the complex of recA protein and single-stranded DNA formed in the presence of single-stranded DNA-binding protein and ATP. D-loops are undetectable when 200 microM adenosine 5'-O-(thiotriphosphate) is substituted ...

The typical biochemical paradigm for coupling between hydrolysis of ATP and the performance of chemical or mechanical work involves a well-defined sequence of events (a kinetic mechanism) with a fixed stoichiometry between the number of ATP molecules hydrolyzed and the turnover of the output reaction. Recent experiments show, however, that such a deterministic picture of coupling may not be ade...