A chemical genetic screen for direct v-Src substrates reveals ordered assembly of a retrograde signaling pathway

Using an ATP analog that is a specific substrate for an analog-specific allele of v-Src, we identified several novel cytoskeletal substrates that control actin assembly processes. A screen for less abundant v-Src substrates revealed the scaffolding protein Dok-1 as a direct substrate of v-Src. Further studies suggest that v-Src phosphorylation sites on Dok-1 are critical for its binding to RasGAP and Csk, negative regulators of Src signaling. This results in the downregulation of growth-promoting signals of the Src family kinases and the Ras pathway. Identification of the direct substrates of v-Src leads to a model for the precise order of assembly of a retrograde signaling pathway in v-Src-transformed cells and has provided new insight into the balance between those signals that promote cell transformation mediated by v-Src catalyzed tyrosine phosphorylation and those that inhibit it.     

Novel annulation reactions : the direct synthesis of cyclopentanes using a lewis acid activated bisfunctional annulating reagent

In a novel one-pot reaction 3,3-Dimethoxy-1-trimethylstannyl-propane (1) reacts in the presence of Lewis acids with O-silytated enolates in a [3+2] annulation to form fused cyclopentanes possessing a bridgehead hydroxy group.     

Photoconductivity of presolvated electrons in ethanol glass at 4 K

Photoconductivity of localized electrons, which are not solvated, in γ-irradiated ethanol glass at 4 K was studied. Photocurrents of 10^?13 A or larger were stably detected in the wavelength range of 900–2200 nm. The wavelength dependence of the photocurrent reveals that pre-solvated electrons probably have no bound excited states.     

Preparation and Cyclization of Aryloxyacetaldehyde Acetals; A General Synthesis of 2,3-Unsubstituted Benzofurans

An improved method for the preparation of 2,3-unsubstituted benzofurans is described. Specifically, the PPA catalysed cyclization of aryloxyacetaldehyde acetals to give (4–7)-substituted benzofurans has been achieved.     

Determination of the deuterium content of deuterated betaine arsenate by electron spin echo envelope modulation

An alternative method for the determination of the deuterium content in the hydrogen bonds of ferroelectric/antiferroelectric deuterated betaine arsenate is presented. Carbon radicals formed by gamma irradiation of the betaine arsenate have been used as paramagnetic probes. The deuterium content in the hydrogen bonds has been determined by analyzing the modulation in the electron spin echo spectra of the carbon radical (CH₃)₃N+CHCOO^? which arises because of the dipolar interactions between the paramagnetic radical and the deuterium nuclei.     

Keto-alkyne cyclisation reactions: heterocyclic prostacyclin analogues

Simple furan, thiophene and pyrrole analogues of prostacyclin have been prepared from readily-available 4-alkvnyl ketones; the cyclohexa[b]-furano-prostacyclin analogue $\text{3}$ has also been synthesised using the keto-alkyne cyclisation procedure.     

Forbidden matrix proton spin flip satelites in 70 GHz ESP spectra of solvated electrons. A geometrical model for the solvated electron in Methanol glass

Proton spin flip satellites have been observed for the first time in the ESR spectrum of solvated electrons in methanol glass at 70 GHz and ≈ 1.5 K. Analysis indicates a solvated electron structure characterized by an electron to OH proton distance of 2.28 ± 0.15 A and 4 ± 2 equivalent first solvation shell methanol molecules. A geometrical model for the solvated electron in methanol glass is suggested.     

Electron spin resonance and optical spectroscopic studies of Co-ZSM-5 with nitric oxide

The reaction of nitric oxide with ZSM-5 zeolite ion-exchanged by Co(II) (Co-ZSM-5) has been studied by electron spin resonance (ESR), Fourier transform infrared (FTIR) and diffuse reflectance ultraviolet-visible spectroscopy. When dehydrated Co-ZSM-5 reacts at room temperature with nitric oxide, the ESR spectrum of Co(II) atg = 5.5, which is only observable below 45 K, is greatly reduced and a new⁵⁹Co hyperfine octet forms at g_avg = 2.11. The overall Co(II) ESR intensity decreases by about 50% which suggests formation of some diamagnetic cobalt complex. Mononitrosyl cobalt complexes such as Co(I)-NO⁺ or less probably Co(III)-(NO)⁻ are suggested as possible precursors of a dintrosyl cobalt complex. The octet indicates hyperfine interaction with⁵⁹Co and is associated with a cobalt dinitrosyl complex. FTIR bands at 1813 and 1896 cm⁻¹ confirm a dinitrosyl species and a broad band from 1600–1800 cm⁻¹ is tentatively interpreted as a mononitrosyl species. The visible spectrum for dehydrated Co-ZSM-5 shows a tetrahedral Co(II) band from 500–700 nm with three components which disappears after NO adsorption at room temperature. We suggest that Co(0)-(NO)₂²⁺ forms after NO adsorption onto Co(II)-ZSM-5 zeolite on the basis of ESR and ultraviolet-visible spectroscopy.