585 research outputs found
Biosynthetic pathway of mitochondrial ATPase subunit 9 in Neurospora crassa
Subunit 9 of mitochondrial ATPase (Su9) is synthesized in reticulocyte lysates programmed with Neurospora poly A-RNA, and in a Neurospora cell free system as a precursor with a higher apparent molecular weight than the mature protein (Mr 16,400 vs. 10,500). The RNA which directs the synthesis of Su9 precursor is associated with free polysomes. The precursor occurs as a high molecular weight aggregate in the postribosomal supernatant of reticulocyte lysates. Transfer in vitro of the precursor into isolated mitochondria is demonstrated. This process includes the correct proteolytic cleavage of the precursor to the mature form. After transfer, the protein acquires the following properties of the assembled subunit: it is resistant to added protease, it is soluble in chloroform/methanol, and it can be immunoprecipitated with antibodies to F1-ATPase. The precursor to Su9 is also detected in intact cells after pulse labeling. Processing in vivo takes place posttranslationally. It is inhibited by the uncoupler carbonylcyanide m- chlorophenylhydrazone (CCCP). A hypothetical mechanism is discussed for the intracellular transfer of Su9. It entails synthesis on free polysomes, release of the precursor into the cytosol, recognition by a receptor on the mitochondrial surface, and transfer into the inner mitochondrial membrane, which is accompanied by proteolytic cleavage and which depends on an electrical potential across the inner mitochondrial membrane
Precursors and post-translational transport of proteins in the assembly of the mitochondrial inner membrane
On thin ice? Arctic indigenous communities, the European Union and the sustainable use of marine mammals
Implicit self-consistent electrolyte model in plane-wave density-functional theory
The ab-initio computational treatment of electrochemical systems requires an
appropriate treatment of the solid/liquid interfaces. A fully quantum
mechanical treatment of the interface is computationally demanding due to the
large number of degrees of freedom involved. In this work, we describe a
computationally efficient model where the electrode part of the interface is
described at the density-functional theory (DFT) level, and the electrolyte
part is represented through an implicit solvation model based on the
Poisson-Boltzmann equation. We describe the implementation of the linearized
Poisson-Boltzmann equation into the Vienna Ab-initio Simulation Package (VASP),
a widely used DFT code, followed by validation and benchmarking of the method.
To demonstrate the utility of the implicit electrolyte model, we apply it to
study the surface energy of Cu crystal facets in an aqueous electrolyte as a
function of applied electric potential. We show that the applied potential
enables the control of the shape of nanocrystals from an octahedral to a
truncated octahedral morphology with increasing potential
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