metaSMT: focus on your application and not on solver integration

International Journal on Software Tools for Technology Transfer - Many applications from artificial intelligence and formal methods use decision procedures as their core solving engines. In this...     

Tracking Protein S‐Fatty Acylation with Proteomics

Recently, Hang and co‐workers developed “acyl‐PEG exchange” (APE), which allows the investigation of protein S‐fatty acylation with mass‐tag labelling and gel electrophoresis, methods that are accessible to any biochemistry laboratory.     

Structure and Substrate Recognition of the Bottromycin Maturation Enzyme BotP

The bottromycins are a family of highly modified peptide natural products, which display potent antimicrobial activity against Gram‐positive bacteria, including methicillin‐resistant Staphylococcus aureus. Bottromycins have recently been shown to be ribosomally synthesized and post‐translationally modified peptides (RiPPs). Unique amongst RiPPs, the precursor peptide BotA contains a C‐terminal “follower” sequence, rather than the canonical N‐terminal “leader” sequence. We report herein the structural and biochemical characterization of BotP, a leucyl‐aminopeptidase‐like enzyme from the bottromycin pathway. We demonstrate that BotP is responsible for the removal of the N‐terminal methionine from the precursor peptide. Determining the crystal structures of both apo BotP and BotP in complex with Mn²⁺ allowed us to model a BotP/substrate complex and to rationalize substrate recognition. Our data represent the first step towards targeted compound modification to unlock the full antibiotic potential of bottro‐ mycin.     

Shock Consolidation of Aluminium Powder with SiC fiber reinforcement

For the explosive compaction of Al 2024 alloy powder the influence of E/M ratio and detonation velocity of the explosive as well as the influences of powder microhardness and initial density are discussed. With a choice of parameters that gives a fully compacted aluminium sample the results of embedding single SiC fibers are described and a procedure to avoid fiber cracking due to shock loads is derived. First results for the compaction of samples with 38% fiber content are presented.     

Measurements of the Refractive Index Increment on Hydroxyethyl Starch as a Basis for Absolute Molecular Weight Determinations

Solutions of hydroxyethyl starch are used as a blood plasma substitute. If their physiological efficiency is to be optimized, they need to be accurately characterized in terms of their molecular weight and its distribution. The absolute determination of molecular weight and molecular weight distribution by means of light scattering require a knowledge of the refractive index increment. Although numerous investigations of the refractive index increment of hydroxyethyl starch have already been published, the results vary significantly due to the use of different samples and the choice of different measuring parameters. There was therefore an urgent need to examine the extent to which the refractive index increment depends on molecular parameters, the experimental method used and the type of processing. Here it was found that different sample preparations result in different contents of solid matter, so that an exact determination of the quantity is required. Hydroxyethyl starches in the molecular weight range of about Mw = 200.000 g/mol and varying degrees of substitution between DS 0.38 and 0.50 which are regarded as optimal for clinical use give a refractive index increment of dn/dc^633nm = 0.146 = 0.005 cm³/g (solvent: H₂O/0.02% NaN₃; T = 25°C).     

119Sn-NMR spektroskopische Untersuchungen an Tributylzinnderivaten aromatischer Sulfonsäuren

¹¹⁹Sn-NMR Spectroscopic Investigations of Tributyltin Derivatives of Aromatic Sulfonic Acids . Tributyltin derivatives of nine aromatic sulfonic acids were synthesized and investigated by means of ¹¹⁹Sn-n.m.r. spectroscopy. ¹¹⁹Sn-chemical shifts and ¹J (Sn, C) coupling constants in dependence on temperature and concentration were applied to study the association processes of the substances in solution. In CDCl₃ as a solvent a monomeric/polymeric equilibrium of the substances was demonstrated, while CD₃OD as a donor solvent forms five-coordinated complexes with the tin compounds.