One-Step Synthesis of Photoaffinity Probes for Live-Cell MS-Based Proteomics.

We present a one-step Ugi reaction protocol for the expedient synthesis of photoaffinity probes for live-cell MS-based proteomics. The reaction couples an amine affinity function with commonly used photoreactive groups, and a variety of handle functionalities. Using this technology, a series of pan-BET (BET: bromodomain and extra-terminal domain) selective bromodomain photoaffinity probes were obtained by parallel synthesis. Studies on the effects of photoreactive group, linker length and irradiation wavelength on photocrosslinking efficiency provide valuable insights into photoaffinity probe design. Optimal probes were progressed to MS-based proteomics to capture the BET family of proteins from live cells and reveal their potential on- and off-target profiles.

Sequestration by IFIT1 impairs translation of 2'O-unmethylated capped RNA.

Viruses that generate capped RNA lacking 2'O methylation on the first ribose are severely affected by the antiviral activity of Type I interferons. We used proteome-wide affinity purification coupled to mass spectrometry to identify human and mouse proteins specifically binding to capped RNA with different methylation states. This analysis, complemented with functional validation experiments, revealed that IFIT1 is the sole interferon-induced protein displaying higher affinity for unmethylated than for methylated capped RNA. IFIT1 tethers a species-specific protein complex consisting of other IFITs to RNA. Pulsed stable isotope labelling with amino acids in cell culture coupled to mass spectrometry as well as in vitro competition assays indicate that IFIT1 sequesters 2'O-unmethylated capped RNA and thereby impairs binding of eukaryotic translation initiation factors to 2'O-unmethylated RNA template, which results in inhibition of translation. The specificity of IFIT1 for 2'O-unmethylated RNA serves as potent antiviral mechanism against viruses lacking 2'O-methyltransferase activity and at the same time allows unperturbed progression of the antiviral program in infected cells.

Spectral control of elastic dynamics in metallic nano-cavities.

We show how the elastic response of metallic nano-cavities can be tailored by tuning the interplay with an underlying phononic superlattice. In particular, we exploit ultrafast optical excitation in order to address a resonance mode in a tungsten thin film, grown on top of a periodic MgO/ZrO2 multilayer. Setting up a simple theoretical model, we can explain our findings by the coupling of the resonance in the tungsten to an evanescent surface mode of the superlattice. To demonstrate a second potential benefit of our findings besides characterization of elastic properties of multilayer samples, we show by micromagnetic simulation how a similar structure can be utilized for magneto-elastic excitation of exchange-dominated spin waves.

Towards multi-order hard X-ray imaging with multilayer zone plates.

This article describes holographic imaging experiments using a hard X-ray multilayer zone plate (MZP) with an outermost zone width of 10 nm at a photon energy of 18 keV. An order-sorting aperture (OSA) is omitted and emulated during data analysis by a 'software OSA'. Scanning transmission X-ray microscopy usually carried out in the focal plane is generalized to the holographic regime. The MZP focus is characterized by a three-plane phase-retrieval algorithm to an FWHM of 10 nm.

Prevalence and prognostic significance of elevated gamma-glutamyltransferase in chronic heart failure.

BACKGROUND: Serum gamma-glutamyltransferase (GGT) is associated with incident cardiovascular diseases and is a potential risk factor for disease mortality. We investigated the relevance of circulating GGT in chronic heart failure. METHODS AND RESULTS: From 2000 to 2007 clinical and laboratory variables of 1033 consecutive outdoor patients with heart failure were evaluated. Follow-up (mean, 34.4 months) was available in 998 patients. The end point was defined as death from any cause or heart transplantation. A forward stepwise Cox proportional hazards regression model for sex-stratified data was used. Prevalence of elevated GGT was 42.9% in men (GGT >65 U/L) and 50.2% in women (GGT >38 U/L), which was higher than for sex- and age-matched healthy subjects (18.6% in men, 19.2% in women) derived from a large historical control group. GGT was associated with severity of heart failure as assessed by New York Heart Association class, left-ventricular ejection fraction, and amino-terminal pro-B-type natriuretic peptide. The end point was recorded in 302 patients. Compared with the lowest GGT quintile, sex-stratified hazard ratios for patients in the highest quintile were 2.88 (1.99 to 4.17) in the univariate model and 1.87 (1.28 to 2.74) in the adjusted model (P<0.001). Corresponding 5-year cumulative event rates were 47% and 74%, respectively. Adjusted hazard ratios for elevated GGT was 2.9 (1.64 to 5.17) for patients in New York Heart Association I/II, and 1.2 (0.75 to 2.05) for patients in New York Heart Association III/IV, respectively (P=0.003, for the GGT-New York Heart Association class interaction). CONCLUSIONS: Prevalence of elevated GGT is high in patients with chronic heart failure. The GGT levels are associated with disease severity. Increased GGT is an independent predictor of death or heart transplantation. GGT may provide additional prognostic information, especially in patients with mild heart failure.