An updated hydrocarbon photochemical model for the Jovian atmosphere from the troposphere through the homopause: A prelude to Galileo

A photochemical model for the atmosphere of Jupiter, including 1-D vertical eddy diffusive transport, was developed. It extends from the upper troposphere through the homopause. The hydrocarbon chemistry involves species containing up to four carbon atoms (and polyynes through C8H2). The calculations show that a large fraction of photochemical carbon may be contained in molecules with more than two carbon atoms. At the tropopause, C2H6 is the major photochemical species and C2H2, C3H8, and C4H10 are of comparable abundance and down from C2H6 by a factor of ten. These species may be detectable with the mass spectrometer of the Galileo Probe. The vertical distributions of the photochemical species are sensitive to the magnitude of eddy diffusive mixing in the troposphere and stratosphere and the details of the interface region

An analysis of the reflection spectrum of Jupiter from 1500 Å to 1740 Å

A study is made of the UV reflection spectrum of Jupiter as measured by the International Ultraviolet Explorer. Detailed modeling reveals the mixing ratios of C_2H_2, C_2H_6, and C_4H_2 to be (1.0 ± 0.1) x 10^(-1), (6.6 ± 5.3) x 10^(-6), and (2.9 ± 2.0) x 10^(-10), respectively, in the pressure region between ~3 and 40 mbar. Upper limits in this pressure region for the mixing ratios of C_2H_4 and NH_3 were determined to be (3.9^(+4.9)_(-3.9))x10^(-10) and (4.2^(+6.7)_(-4.2))x10^(-9), respectively. An upper limit to the optical depth of dust above the tropopause, assuming it is well mixed, is 0.2^(+0.3)_(-1.4), and an upper limit on the dayglow emission by the Lyman bands of H_2 is 1.4^(+2.4)_(-1.4) kR. Comparison with Voyager results suggests that the scale height of C_2H_2 in the region 150-10 mbar is approximately twice that of the bulk atmosphere, consistent with the IUE observation of cosine-like limb darkening in the north-south direction on Jupiter in this spectral range. These results are of use in the photochemical modeling of the upper atmosphere of Jupiter

7D-Grid-AI-Technology: A technology that translates enzymes from a computer to business with limited lab experiments

Please click Additional Files below to see the full abstract

The atmosphere of Pluto as observed by New Horizons

In July 2015, the New Horizons spacecraft flew through the Pluto system at high speed, humanity's first close look at this enigmatic system on the outskirts of our solar system. In a series of papers, the New Horizons team present their analysis of the encounter data downloaded so far: Moore et al. present the complex surface features and geology of Pluto and its large moon Charon, including evidence of tectonics, glacial flow, and possible cryovolcanoes. Grundy et al. analyzed the colors and chemical compositions of their surfaces, with ices of H_2O, CH_4, CO, N_2, and NH_3 and a reddish material which may be tholins. Gladstone et al. investigated the atmosphere of Pluto, which is colder and more compact than expected and hosts numerous extensive layers of haze. Weaver et al. examined the small moons Styx, Nix, Kerberos, and Hydra, which are irregularly shaped, fast-rotating, and have bright surfaces. Bagenal et al. report how Pluto modifies its space environment, including interactions with the solar wind and a lack of dust in the system. Together, these findings massively increase our understanding of the bodies in the outer solar system. They will underpin the analysis of New Horizons data, which will continue for years to come

7D QSAR based grid maps generated using quantum mechanic probes to identify hotspots and predict activity of mutated enzymes for enzyme engineering

Use of Quantum Mechanics hybridized with Molecular Mechanics (QM/MM) in Enzyme studies have greatly accelerated the finding of intermediate states of enzymatic reactions. The gaps in the conventional methods are in the identification of hot spots and screening enzyme variants. As a proof of concept, for the first time, receptor dependent – 4D Quantitative Structure Activity Relationship (RD-4D-QSAR) to predict kinetic properties of enzymes was demonstrated by Pravin Kumar et al, presented in Enzyme Engineering XXII, 2013, Toyama. We have extended this methodology to study enzymes using 7D-QSAR based grid maps. Induced-fit scenarios were explored using QM/MM simulations, which was then placed in a grid that stores interactions energies derived from QM parameters (QMgrid). The novelty of this method is that the mutated enzymes are immersed completely inside the QMgrid and this is combined with solvation models to predict descriptors; the grid captures the accurate electronic details of the reaction at very high resolution. Every grid point here is a probe, which are atoms that mimic atoms of the substrate interacting with the atoms of the enzyme, also atoms of the enzyme interacting with itself. The probes with its reaction coordinates are mapped on the ES complex conformations derived from ES, enzyme-transition and enzyme-product stages. The statistically relevant conformations are derived after screening using knowledge-based energy scoring matrices. The grid map shows high energy and low energy reactions across the ES system, which is used to pick hotspots. A substitution matrix is automatically constructed on the chosen hotspots using an evolutionary based scoring matrix coupled with statistical modelling process that gives the suited amino acids for a specific hot spot. We have tested this on a specific transaminase and QSAR models showed \u3e90% specificity and \u3e85% sensitivity towards the experimental activity with enzyme variants. Mapping descriptors on the enzyme structure revealed hotspots important to enhance the enantioselectivity of the enzyme. The method is efficient to design enzymes and proteins with minimum of double extending upto seven mutations on its own. Please click Additional Files below to see the full abstract

Engineering of a specific CYP450 for an industrial process shows 700-fold increase in activity with Kcat of 6.2 s-1 - Residues causing Hydrogen Migration and Double Hydrogen Abstraction at Δx Carbon identified by Quantum Mechanics revealed to be the game

V3 2 32.7 and 33.8 3.5±0.5 Figure 1A. – Cyp450 complexed with heme and substrate integrated in the yeast hypo membrane B. Shows the rate limiting transitions state of the enzymatic reaction Table 1 – Energies of the crucial transition states and the experimental Kcat values A CYP450 catalyzed desaturation reaction for the synthesis of an Active Pharmaceutical Ingredient (API) via biocatalytic route that is estimated to top up the revenue of the company to 8.5 million dollars was identified in this study. Currently this route is being tested for the industrial scale production of the API. This was achieved by engineering a specific membrane bound CYP450 enzyme that was initially inactive towards the substrate. Extensive modelling studies were carried out to obtain an initial promiscuous activity (0.53/min). Here the substrate enters through the transmembrane region of the enzyme that acts as a tunnel and moves to the Heme Binding Site in the CYP450 during which it undergoes rotation of ~180°. The substrate entry was identified as the first rate limiting step in the reaction. Using a grid-based path optimization method this path was engineered to facilitate the easy entry and movement of substrate in to the active site. The second rate limiting step was observed in the formation of two transition states of the reaction which was identified using Quantum Mechanics hybridized with Molecular Mechanics (QM/MM) simulations. The enzyme was engineered using quantum polarized grid technology to reduce the energy of these transition states. The mutations introduced, improved the enzyme activity \u3e 700 folds giving a Kcat value of 6.2s-1 which translated to a good yield of the product in the lab scale fermenter. A greater finding in this project is the desaturation reaction mechanisms involving the hydrogen migration and double hydrogen abstracted from the same ΔX Carbon. This was obtained using extensive QM/MM simulations studies and a high-resolution grid energy evaluation method which revealed transition and intermediate states of the reaction, not reported before in any of the desaturation mechanisms solved so far. Some important aspects of this study include, modelling yeast membrane with different lipids and varying substrate concentrations, enzyme behavior at high substrate concentrations and process optimization. In conclusion, this is a cost effective route with a conversion rate that is ~10 times more than the chemical route. This process can be applied to engineer CYP450 for any chemical routes that involve a desaturation reaction Please click Additional Files below to see the full abstract