Adenylate translocator

Kanaani J, Ginsburg H (1989) Metabolic interconnection between the human malarial parasite Plasmodium falciparum and its host erythrocyte. Regulation of ATP levels by means of an adenylate translocator and adenylate kinase. J Biol Chem 264(6) 3194-3199... 

Pozueta-Romero, J., Frehner, M., Viale, A. M., and Akazawa, T. 1991. Comparative analysis of mitochondrial and amyloplast adenylate translocators. FEBS Lett. 287, 62-66. 

SHANNON, J.C., PIEN, F.M., CAO, H., LIU, K.C., Brittle-1, an adenylate translocator, facilitates transfer of extraplastidial s)mthesized ADP-glucose into amyloplasts of maize endosperm. Plant Physiol., 1998,117, 1235-1252. 

Other oncogenes code for proteins that bind guanine nucleotides, and others code for nuclear proteins. The guanine nucleotide-binding proteins, the so-called G proteins, affect several key reactions. Some G proteins are stimulatory, whereas others are inhibitory. For example, they link hormone receptors to adenylate cyclase, they translocate... 

In parallel, activity of adenylate cyclase is inhibited by Ca2+, and the ion activates the membrane-embedded CAM to close the cAMP-dependent channels. In addition, CAM-PDE is induced to hydrolyze the messenger molecules rapidly. 4) Finally, Ca2+ activates the cytoplasmic CAM to enhance the activity of Ca2+-translocating ATPase, causing the cells to return to the resting state. 

Figure 4 Single reactions in NRPSs and their timing, (a) After ribosomal synthesis of the opo-enzymes, the PCP domains are postsynthetically modified with 4 -Phosphopantetheine cofactors by a 4 Ppan transferase, e.g., Sfp. (b) In a second step, the A domains bind their cognate substrates as well as ATP and form the corresponding acyl-adenylate intermediates. These are transferred onto the cofactor of the neighboring PCP domains, (c) The C domains catalyse the condensation of two building blocks. The specificities of C domains and the affinities of aminoacyl-/peptidyl-ho/o-PCP domains ensure that no internal start reactions occur (d) Only after the first condensation domain has acted does the second C domain seem to process the intermediate. During synthesis, the growing product chain is continuously translocated toward the C-terminal end of the enzyme.

Ax subunit which translocates within the cell membrane and activates the adenylate cyclase system. 

In non-i ibosomal biosynthesis of peptide antibiotics by multimodular synthetases, amino acid monomers ai e activated by the adenylation domains of the synthetase and loaded onto the adjacent canier protein domains as thioesters, then the formation of peptide bonds and translocation of the growing chain are effected by the synthetase s condensation domains. Whether the condensation domains have any editing function has been unknown. Synthesis of aminoacyl-CoA molecules and direct enzymatic transfer of aminoacyl-phospho-pantetheine to the caiiier domains allow the adenylation domain editing function to be bypassed. This method was used to demonstrate that the first condensation domain of tyroci-dine synthetase shows low selectivity at the donor residue (D-phenyManine) and higher selectivity at the acceptor residue (L-proline) in the formation of the chain-initiating D-Phe-L-Pro dipeptidyl-enzyme intermediate. 

Strasser, R.H., Benovic, J.L., Caron, M.G. and Lefkowitz, R.J. (1986). )9-agonist- and prostaglandin Ej-induced translocation of the )5-adrenergic receptor kinase Evidence that the kinase may act on multiple adenylate cyclase-coupled receptors. Proc. Natl. Acad. Sci. USA, 83, 6362-6366... 

In detail, the 3 -hydroxy-group of the ribose (in the terminal adenosine residue of each tRNA molecule) is acylated, enzymatically, by an activated form of that amino acid for which this tRNA is specific. Amide-ester exchange of these esters with peptidyl-tRNA on the ribosomes then occurs under the direction of mRNAs. In the latter step, the growing peptide is transferred from the tRNA bond on the donor site of the ribosomes to an aminoacyl-tRNA bond on the acceptor site of the same ribosome. This reaction is catalysed by the enzyme peptidyl transferase. The peptide, lengthened in this way, is then entirely shifted to the donor site with the help of a translocation enzyme. The next aminoacyl-tRNA then becomes bound to the vacant acceptor site, and the process is repeated. The terminal groups of the tRNAs are always —XCCA, where C is a cytidylic, and A an adenylic, acid residue. 

Freshly isolated, intact mitochondria contain considerable amounts of adenine nucleotides which are resistant to removal by repeated washings with isotonic sucrose. This indicates that these compounds are in a compartment—presumably within the inner mitochondrial membrane—which is inaccessible to the sucrose solution. When exogenous adenine nucleotide is added to the mitochondria, there is a rapid exchange with endogenous adenine nucleotides with no net increase in the concentration of adenine nucleotides in the mitochondria. ADP exchanges most rapidly, followed by ATP and then by AMP, which is relatively impermeable. It is the inner mitochondrial membrane through which the adenine nucleotides do not permeate and which contains the specific adenine-nucleotide transporting system. The movement of ATP across the inner mitochondrial membrane (and hence out of the mitochondria) depends directly on the translocation of ADP in the presence of adenylate kinase in the outer compartment of the mitochondria. 

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