IN ADDITION TO SERVING as components of nucleic acids and central players in intracellular energy metabolism, adenosineand guanosine-based metabolites play critical but distinct roles in signal transduction processes. ATP has two major functions in intracellular signaling. It serves as the principal nucleotide phosphate donor for the myriad protein kinases that act as molecular switches for mos...

Optical rotatory dispersion and circular dichroism have been used to investigate the protonation of guanosine and some of its analogues. An inversion of the principal Cotton effect and the dichroic band is observed below the acid pK. It is suggested that a conformational change from the anti form above the pK to the syn form below the pK occurs. The reasons why this change should occur only in ...

1. Urinary cyclic nucleotide excretion was studied in 51 patients with malignant tumours and in 24 control subjects. 2. Adenosine 3':5'-cyclic monophosphate excretion was normal in patients with tumours. 3. Urinary excretion of guanosine 3':5'-cyclic monophosphate was significantly greater than normal in patients with lymphoid tumours (both sexes) and in male patients with myeloid tumours or ma...

The Rag family of guanosine triphosphatases (GTPases) regulates eukaryotic cell growth in response to amino acids by activating the target of rapamycin complex 1 (TORC1). In humans, this pathway is often deregulated in cancer. In yeast, amino acids promote binding of GTP (guanosine 5'-triphosphate) to the Rag family GTPase Gtr1, which, in combination with a GDP (guanosine diphosphate)-bound Gtr...

Elongation factor G (EF-G) is a guanosine triphosphatase (GTPase) that plays a crucial role in the translocation of transfer RNAs (tRNAs) and messenger RNA (mRNA) during translation by the ribosome. We report a crystal structure refined to 3.6 angstrom resolution of the ribosome trapped with EF-G in the posttranslocational state using the antibiotic fusidic acid. Fusidic acid traps EF-G in a co...

The development of the luminescence system in Beneckea harveyi is controlled by cyclic nucleotides at the level of transcription. In the wild type, it is repressed by exogenously added guanosine 3':5'-cyclic monophosphate and this repression is overcome by the addition of adenosine 3':5'-cyclic monophosphate. These observations alone support a model in which these nucleotides act antagonistical...