Atomic force spectroscopy, a technique derived from Atomic Force Microscopy (AFM), allowed us to distinguish nonspecific and specific interactions between the acetolactate synthase enzyme (ALS) and anti-atrazine antibody biomolecules and the herbicides imazaquin, metsulfuron-methyl and atrazine. The presence of specific interactions increased the adhesion force (F adh ) between the AFM tip and the herbicides, which made the modified tip a powerful biosensor. Increases of approximately 132% and 145% in the F adh values were observed when a tip functionalized with ALS was used to detect imazaquin and metsulfuron-methyl, respectively. The presence of specific interactions between the atrazine and the anti-atrazine antibody also caused an increase in the F adh values (approximately 175%) compared to those observed when using an unfunctionalized tip. The molecular modeling results obtained with the ALS enzyme suggest that the orientation of the biomolecule on the tip surface could be suitable for allowing interaction with the herbicides imazaquin and metsulfuron-methyl.

No abstract

No abstract

No abstract

No abstract

A combined molecular modeling and molecular dynamics simulation was carried out to obtain an improved description of the yeast acetohydroxyacid synthase (AHAS) in aqueous solution. After a thorough homology modeling, the AHAS catalytic dimer was subjected to a molecular dynamics (MD) simulation to analyze its behavior and optimize its geometry. The AHAS 3D molecular structure was analyzed according to the number of salt bridges and hydrogen bonds formed. During 20 ns of MD simulation, an average fluctuation of 3.9 Å was obtained. The cofactor thiamine diphosphate makes a relevant contribution to the system stability; this hypothesis was confirmed by the decrease in the average fluctuation of 0.3 Å. Moreover, the Ramachandran plot revealed no denaturation framework during the time of the simulation. ]]>

No abstract

In this paper, one discusses the effects of Tsallis entropy on the radial pressure distribution in the proton. Using a damped confinement potential the pressure distribution is obtained from the Tsallis entropy approach, being the entropic-index [Formula: see text] connected with the proton temperature concerning some transition temperature. Then, the approach allows the study of the proton thermal evolution up to the Quark–Gluon Plasma regime. The von Laue stability condition, arising from the pressure distribution results in positive and negative energy regions. An analogy between the results for the radial pressure distribution and the proton–proton and the antiproton–proton total cross-section is performed. The negative energy region is identified with the odderon exchange while the positive represents the pomeron exchange dominance above some transition energy [Formula: see text]. The hollowness effect is also discussed in terms of the results obtained and the proposed analogy.