Understanding the riddle of amine oxidase flavoenzyme reactivity on the stereoisomers of N-methyl-dopa and N-methyl-tyrosine.

Enzymes are usually stereospecific against chiral substrates, which is commonly accepted for the amine oxidase family of enzymes as well. However, the FsqB (fumisoquin biosynthesis gene B) enzyme that belongs to the family of sarcosine oxidase and oxidizes L-N-methyl-amino acids, shows surprising activity for both enantiomers of N-methyl-dopa. The aim of this study is to understand the mechanism behind this behavior.

Inhibition of the Peroxygenase Lytic Polysaccharide Monooxygenase by Carboxylic Acids and Amino Acids.

Lytic polysaccharide monooxygenases (LPMOs) are widely distributed in fungi, and catalyze the oxidative degradation of polysaccharides such as cellulose. Despite their name, LPMOs possess a dominant peroxygenase activity that is reflected in high turnover numbers but also causes deactivation. We report on the influence of small molecules and ions on the activity and stability of LPMO during catalysis.

BuRNN: Buffer Region Neural Network Approach for Polarizable-Embedding Neural Network/Molecular Mechanics Simulations.

Hybrid quantum mechanics/molecular mechanics (QM/MM) simulations have advanced the field of computational chemistry tremendously. However, they require the partitioning of a system into two different regions that are treated at different levels of theory, which can cause artifacts at the interface. Furthermore, they are still limited by high computational costs of quantum chemical calculations.

UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase from the snail Biomphalaria glabrata - structural reflections.

UDP-GalNAc:polypeptide GalNAc transferase (ppGalNAcT; EC 2.4.1.

From phenols to quinones: Thermodynamics of radical scavenging activity of para-substituted phenols.

Radical scavenging activity and subsequent oxidation resulting in quinone products represent one of the important features of phenols occurring in plants and other biological systems. However, corresponding thermochemistry data can be still considered scarce. For phenol and 25 para-substituted phenols, we investigate the thermodynamics of the individual reaction steps, including three subsequent hydrogen atom transfers, as well as hydroxyl HO radical addition, leading to final ortho-quinone formation.

Thermodynamics of radical scavenging of symmetric carotenoids and their charged species.

For nine symmetric natural carotenoids, a comprehensive thermodynamics study of processes associated with their radical scavenging activity is proposed. We have investigated the hydrogen atom transfer (HAT) from the parent carotenoid, mono-radical species, radical cations and radical anions. Electron transfer and proton transfer reactions were also studied.

B3LYP Study of 3-hydroxynaphthalene-2-carboxanilide para-derivatives.

A systematic DFT investigation of 3-hydroxy-N-phenylnaphthalene-2-carboxamide and its sixteen para-derivatives is presented. The structural analysis showed that the energetically preferred conformation of all derivatives is practically planar and it is stabilised via intramolecular hydrogen bonds occurring between (C)O..

Polyradical PROXYL/TEMPO-Derived Amides: Synthesis, Physicochemical Studies, DFT Calculations, and Antimicrobial Activity.

A series of polynitroxide amides possessing 2,2,5,5-tetramethyl-1-pyrrolidinyloxy (PROXYL) and/or 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) units connected through various bridges were synthesized and their properties were analyzed. EPR spectroscopy provided detailed insight into their paramagnetic character and related properties. A thorough examination of the EPR spectra of dinitroxides in organic solvents provided valuable information on the intramolecular motions, thermodynamics, and spin-exchange mechanisms.