Search results for "Chemical activity"
showing 5 items of 5 documents
Electrostatic complementarity in pseudoreceptor modeling based on drug molecule crystal structures: the case of loxistatin acid (E64c)
2015
After a long history of use as a prototype cysteine protease inhibitor, the crystal structure of loxistatin acid (E64c) is finally determined experimentally using intense synchrotron radiation, providing insight into how the inherent electronic nature of this protease inhibitor molecule determines its biochemical activity. Based on the striking similarity of its intermolecular interactions with those observed in a biological environment, the electrostatic potential of crystalline E64c is used to map the characteristics of a pseudo-enzyme pocket.
Light-induced structural changes in a monomeric bacteriophytochrome
2016
International audience; Phytochromes sense red light in plants and various microorganism. Light absorption causes structural changes within the protein, which alter its biochemical activity. Bacterial phytochromes are dimeric proteins, but the functional relevance of this arrangement remains unclear. Here, we use time-resolved X-ray scattering to reveal the solution structural change of a monomeric variant of the photosensory core module of the phytochrome from Deinococcus radiodurans. The data reveal two motions, a bend and a twist of the PHY domain with respect to the chromophore-binding domains. Infrared spectroscopy shows the refolding of the PHY tongue. We conclude that a monomer of th…
Influence of clouds on the spectral actinic flux density in the lower troposphere (INSPECTRO): overview of the field campaigns
2008
Ultraviolet radiation is the key factor driving tropospheric photochemistry. It is strongly modulated by clouds and aerosols. A quantitative understanding of the radiation field and its effect on photochemistry is thus only possible with a detailed knowledge of the interaction between clouds and radiation. The overall objective of the project INSPECTRO was the characterization of the three-dimensional actinic radiation field under cloudy conditions. This was achieved during two measurement campaigns in Norfolk (East Anglia, UK) and Lower Bavaria (Germany) combining space-based, aircraft and ground-based measurements as well as simulations with the one-dimensional radiation transfer model UV…
Flow Cytometry versus Fluorescence Microscopy
1996
Since the pioneer work of the botanist Matthias Jakob Schleiden and the zoologist Theodor Schwann in 1839, and of Rudolph Virchow in 1859, cell research progressed in two opposite directions. Cell biologists focused their increasingly more powerful microscopies into the cell structure to reveal the great morphological complexity of the cytoplasm. A growing number of subcellular organelles thus challenged the early biochemists to discover their specific molecular features and their coordination to maintain an ordered cell life. The biochemists’ answer to such a challenge consisted usually in tearing apart cells into their discrete components and obtaining information on molecules and pathway…
Drug Activity Characterization Using One-Class Support Vector Machines with Counterexamples
2013
The problem of detecting chemical activity in drugs from its molecular description constitutes a challenging and hard learning task. The corresponding prediction problem can be tackled either as a binary classification problem (active versus inactive compounds) or as a one class problem. The first option leads usually to better prediction results when measured over small and fixed databases while the second could potentially lead to a much better characterization of the active class which could be more important in more realistic settings. In this paper, a comparison of these two options is presented when support vector models are used as predictors.