Contribution Of Functional Groups Research Articles

Species-specific nitrogen resorption proficiency in legumes and nonlegumes.

Nitrogen (N) resorption from senescing leaves enables plants to reuse N, thereby making them less dependent on current N uptake from the environment. Therefore, N resorption is important for survival and fitness, particularly for plants growing under low N supply. We studied N resorption from senescing leaves of 25 legumes and 25 nonlegumes in a temperate region of Japan to test the hypothesis that high N resorption has not evolved in legumes that fix atmospheric N2. The extent of N resorption was quantified by N resorption proficiency that is measured as the level to which leaf N concentration was reduced during senescence, i.e., the lower the senesced leaf N concentration, the lower the N loss through leaf fall and higher the N resorption proficiency. In support of the hypothesis, senesced leaf N concentration was higher in legumes than in nonlegumes, but there was considerable overlap between the groups. The higher senesced leaf N concentration of legumes was associated with a lower proportion of leaf N resorbed during senescence, particularly in species with higher leaf N concentrations. According to a hierarchical partitioning analysis, there was a large contribution of species to the total variance in the senesced leaf N concentration as opposed to a minor contribution of functional group (legume/nonlegume). This study reveals that legumes are not proficient at resorbing N from senescing leaves but that N2-fixation might not be the single most important determinant of N resorption.

Restoring functionally diverse communities enhances invasion resistance in a freshwater wetland

Abstract Understanding how plant communities reassemble is particularly relevant when invaders are part of the species pool and can compromise restoration or conservation goals. If initial species composition has a lasting impact on community dynamics, it may be possible to enhance biotic resistance to invasion, particularly through diversity effects, by manipulating early community composition. Diversity effects have been investigated much less in wetlands than in uplands. We conducted a large plant community restoration experiment in a freshwater wetland to investigate species and functional diversity effects on biotic resistance to invasion during early community assembly. The wetland was under propagule pressure mostly from Phragmites australis (common reed), but all species not sown in this experiment that established in the plots were treated as ‘invaders’, whether exotic or native. We used a two‐step model selection approach and a diversity‐interaction model framework to test hypotheses about the contribution to invasion success of abiotic conditions, species richness, as well as functional group richness, identity and pairwise interactions, providing a rare test of diversity effects against multiple invaders in wetlands. In all, 20 species invaded the plots. They were grouped for analysis to evaluate the overall resistance of resident communities. The three main invaders, P. australis and two native taxa (Salix spp., Populus deltoides), were also analysed separately. Diversity‐interaction models revealed invader‐specific responses. Functional group identity determined resistance to P. australis, whereas pairwise interactions between functional groups explained resistance to Salix spp. Both effects were retained when grouping all invaders. Resistance to P. deltoides was determined by abiotic conditions. The contribution of specific functional groups varied with invader. Annuals and clonal perennials explained resistance to P. australis, suggesting priority and limiting similarity effects. Interactions, when significant, mostly included fast‐growing annuals. When considering all invaders, identity effects were detected for all functional groups. Synthesis. Diversity effects on invasion resistance vary with invaders in early assembly of restored wetland communities. Restoring functionally diverse communities provides resistance against multiple invaders. Consistent responses between this field experiment and previous pot experiments with the same species suggest that results are robust enough to inform management.

Acetone adsorption on activated carbons: Roles of functional groups and humidity

Activated carbon (AC) materials has been widely used to prevent acetone pollution. In such process, the modification of AC is an effective way to improve the adsorption capacity of acetone. Therefore, the understanding of modification mechanism is the first and the most critical step in optimizing the preparation design and application of AC. A series of grand canonical Monte Carlo (GCMC) simulations was performed with models that were constructed from a collection of flat coronene-shaped graphitic basic units to systematically investigate the effect of different functional groups (i.e., OH, COOH, =O, NH2, and NO2) in the presence or absence of humidity. The AC isotherms obtained from the simulation model were well consistent with those obtained from experiments based on the premise that ACs had similar surface areas. Our results demonstrated that different functional groups under the same condition provided different non-electrostatic contribution and electrostatic contributions to acetone adsorption capacity. The electrostatic contribution of oxygen-containing functional groups was better than that of nitrogen-containing functional groups, and functional groups containing oxygen and hydrogen were better than the functional groups containing only oxygen. Humidity resulted in the pronounced decrease in the non-electrostatic contribution to all functional groups. However, electrostatic contribution under humidity is less affected by humidity.

Contributions of Different Functional Groups to Contact Electrification of Polymers.

Polymers are commonly used to fabricate triboelectric nanogenerators (TENGs). Here, several polymer films with similar main chains but different functional groups on the side chain are employed to clarify the contributions of each functional group to contact electrification (CE). The results show that the electron-withdrawing (EW) ability and density of these functional groups on the main chain can determine both the polarity and density of CE-induced surface charges. Similar results are obtained for CE in both the polymer-polymer and polymer-liquid modes. A theoretical mechanism involving electron cloud overlap is proposed to explain all of these results. More importantly, the unsaturated groups on poly(tetrafluoroethylene) molecular chain are proved to have a much stronger EW ability than the saturated groups. The density of these unsaturated groups can be increased using a sputtering technique, suggesting that this is a facile and effective method of enhancing the performance of TENGs. These results clarify the correlation between the molecular structure and macroscopic electrification behavior of polymers.

Thermodynamic characteristics of the adsorption of benzene derivatives from water—organic eluents on porous graphite-like adsorbent under conditions of equilibrium HPLC

Thermodynamic characteristics of the adsorption of benzene and its derivatives on the surface of a porous graphite-like Hypercarb adsorbent from binary polar eluents have been experimentally determined under the conditions of equilibrium HPLC at various temperatures. The retention on Hypercarb columns is generally maintained by non-specific intermolecular interactions with the flat graphite-like surface and depends on the size of their molecular area. The contributions of various functional groups to the heat and entropy of adsorption were determined. The influence of solvation effects on the values of adsorption parameters was demonstrated. The replacement of methanol in the mobile phase composition with acetonitrile leads to an increased influence of the solvatation effects, while for the water-acetonitrile eluent, there were no any observed correlations of parameters of the adsorption on Hypercarb from a water-methanol medium with the data acquired on gas phase adsorption on graphite. The entropy values of adsorbates in their solvated state have been for the first time determined for eluents of the different polarities and compared with the entropy values for the state of pure liquid, which allowed us to clarify the nature of solvatation of the considered compounds in the polar eluent. Using the adsorption of compounds at issue as an example, the effect of enthalpy-entropy compensation was investigated, and the values of compensation temperatures were estimated.

The role of solvents and oxygen-containing functional groups on the adsorption of Bisphenol A on carbon nanotubes

ABSTRACT The wide application of endocrine disruptors (EDs) has recently created great public concerns because of their toxicities. Previous studies have stated that the effect of oxygen-containing functional groups of carbon nanotubes (CNTs) for Bisphenol A (BPA) sorption, but no study has been quantified the exact contribution of the oxygen-containing functional groups. Moreover, the role of solvents on the adsorption of BPA should be considered. Considering the well properties of CNTs, graphitized (MG), carboxylated (MC) and hydroxylated (MH) multi-walled CNTs were selected as model adsorbents, BPA was used as model adsorbate. Solubility and single point adsorption coefficient (logK d) of BPA were n-hexadecane > water > methanol, suggesting that hydrophobic interaction was the main mechanism for BPA sorption on CNTs. For different functional groups of CNTs, π-π interaction between MH and BPA may be stronger than that of MC, and thus the sorption of BPA on MH was higher than that of MC. Moreover, hydrogen bond resulted in the higher adsorption of BPA on MH when compared with MC. The oxygen-containing functional groups of CNTs played a key role for BPA sorption in methanol because the values of contribution were 20%–45% for -OH and were 5%–25% for -COOH. In n-hexadecane, other factors such as hydrophobic interactions should be considered because the contribution percentages of -OH were ca.15% and the values for -COOH were ca.10%. The results are expected to provide important information on the interaction of EDs and CNTs.

Exploring water-soluble organic aerosols structures in urban atmosphere using advanced solid-state 13C NMR spectroscopy

Abstract Water-soluble organic matter (WSOM) in air particles has profound effects on climate and human health. At the heart of this environmental significance of WSOM lies a complex set of compounds, of which a major fraction still often remains undeciphered. Yet, not all environmental problems require delving into the molecular-level identification of WSOM constituents. Understanding the contribution of different functional groups to whole aerosol WSOM composition offers a highly important structural dataset that enables a better representation of WSOM in climate studies. For the first time, advanced solid-state 13C nuclear magnetic resonance (NMR) techniques, including nearly quantitative 13C multiple cross polarization/magic angle spinning (multiCP/MAS), multiCP/MAS with dipolar dephasing, multiCP/MAS with 13C chemical shift anisotropy filter, and two-dimensional 1H–13C heteronuclear correlation (2D HETCOR), are applied to acquire an accurate quantitative structural description of whole aerosol WSOM collected in an urban atmosphere. Two urban aerosol WSOM samples collected in two short periods of time, under different wintry weather conditions, were investigated. NMR data successfully pinpointed the variability of whole aerosol WSOM composition, allowing to suggest source-specific structural characteristics for each sample in two short periods of time. A new structural model of urban aerosol WSOM was build based on this compositional data, showing the presence of three independent classes of compounds that vary both in content and molecular diversity within short periods of time: heteroatom-rich aliphatic (either chain or branched), carbohydrate-like moieties, and highly substituted aromatic units. These findings establish advanced solid-state NMR as a promising tool for probing the chemical structures of inhomogeneous aerosol WSOM in rapidly changing atmospheric conditions, allowing to resolve discrepancies between modeled and measured aerosol WSOM.

Amino and hydroxy substitution influences pyrene–DNA binding

Polycyclic aromatic hydrocarbon (PAH)–DNA binding is an essential step in PAH-induced carcinogenesis. A large number of PAHs contain substituents, it is unclear whether functional groups will influence the PAH–DNA binding. Here, we investigated amino (-NH2) and hydroxy (-OH) substitution on pyrene–DNA binding. Because of the considerable effects of electrostatic surface potential (ESP), -NH2 substitution significantly facilitated binding by increasing the binding constant (log KA) from 4.14 L mol−1 to 12.31 L mol−1, while -OH substitution inhibited binding by reducing log KA to 3.68 L mol−1. Spectroscopy results revealed that pyrene and its derivatives were able to bind with thymine to induce DNA damage or double helix distortion. Quantum chemical calculations showed that -NH2 substitution induces hydrogen bond formation, thereby enhancing the binding of pyrene with DNA; moreover, binding force changes due to -OH substitution may not be an essential factor. All structural descriptors were not correlated with the quenching constant (KSV) or binding constant, indicating that changes in physicochemical properties shows no influence on pyrene–DNA binding. The results of this study will improve our understanding of the contribution of functional groups to PAH–DNA binding.

Dissecting Amino Acid Osmolytes: Is a Zwitterion Required for Increasing Protein Thermal Stability?

Amino acids are an important class of osmolytes that demonstrate the ability to stabilize certain proteins under acute thermal stress. However, little consensus exists on what structural aspects produce this phenomenon. It has been proposed that the stabilizing nature of amino acids emerges from their zwitterionic nature at neutral pH, but little evidence has supported this view, especially in regards to the breadth of its applicability to proteins of varying structure and composition. In this report, we structurally dissect the amino acids L‐alanine and β‐alanine to determine functional group contributions to protein‐stabilizing activity on two structurally dissimilar proteins: human C‐reactive protein (CRP) and human myoglobin. The stabilizing effects of the osmolytes (and their structural derivatives) were quantified by Differential Scanning Fluorimetry (DSF) in three metrics: protein melting temperature (Tm), standard free energy change (ΔGo), and “m”‐values. Our results indicate that the zwitterionic theory holds for myoglobin, as removal of either the carboxylate or amino moiety from the amino acid abrogated all thermal stabilizing effects. Furthermore, substitution of the carboxylate group with a hydroxyl group did not restore protein‐stabilizing activity, arguing for the zwitterionic requirement for amino acid‐mediated thermal stabilization. However, the results with CRP were significantly different from those observed with myoglobin. In the case of CRP, the amino acid carboxylate proved to be the dominant stabilizing group, as compounds lacking the amino group conferred greater thermal stability than the complete amino acids. These results affirm that the zwitterionic theory is limited in its ability to describe amino acid‐mediated effects on protein thermal stability and suggests that the nature of the interactions between amino acid osmolytes and proteins is highly dependent on protein structure. These results may have significant implications for the development of chemistries to stabilize diverse protein targets in biospecimens for diagnostic applications.Support or Funding InformationCalifornia State University Program for Education and Research in Biotechnology (CSUPERB)Chevron Biotechnology Applied Research EndowmentBill and Linda Frost Fund

Optimizing Multivariate Metal-Organic Frameworks for Efficient C2H2/CO2 Separation.

Adsorptive separation of acetylene (C2H2) from carbon dioxide (CO2) promises a practical way to produce high-purity C2H2 required for industrial applications. However, challenges exist in the pore environment engineering of porous materials to recognize two molecules due to their similar molecular sizes and physical properties. Herein, we report a strategy to optimize pore environments of multivariate metal-organic frameworks (MOFs) for efficient C2H2/CO2 separation by tuning metal components, functionalized linkers, and terminal ligands. The optimized material UPC-200(Al)-F-BIM, constructed from Al3+ clusters, fluorine-functionalized organic linkers, and benzimidazole terminal ligands, demonstrated the highest separation efficiency (C2H2/CO2 uptake ratio of 2.6) and highest C2H2 productivity among UPC-200 systems. Experimental and computational studies revealed the contribution of small pore size and polar functional groups on the C2H2/CO2 selectivity and indicated the practical C2H2/CO2 separation of UPC-200(Al)-F-BIM.

Novel Functional Group Contribution Method for Surrogate Formulation with Accurate Fuel Compositions

Current surrogate formulation methods usually adopt distillation profiles, density, viscosity, surface tension, molecular weight, research/motor octane number (RON/MON), cetane number (CN), heating...

Functional Groups of Phytoplankton and Their Relationship with Environmental Factors in the Restored Uzarzewskie Lake

Uzarzewskie Lake is a small, postglacial lake, located in western Poland. The lake is under restoration treatment since 2006. At first, iron treatment was done for 2 years. In the second stage, spring water was directed into the hypolimnion in order to improve water oxygenation near the bottom sediments. The purpose of our research was to determine changes in the contribution of functional groups to the total number of taxa and total biomass of phytoplankton due to changes in the physical and chemical characteristics of the restored lake. Phytoplankton composition was analyzed in three periods: (1) before restoration; (2) during the first method of restoration; and (3) when the second method was implemented in the lake. Epilimnetic phytoplankton was sampled every year monthly from March to November. The relationship between phytoplankton groups and environmental factors (water temperature, ammonium nitrogen, nitrate nitrogen, dissolved phosphorus, conductivity and pH) was examined, using the canonical analyses. The redundancy analysis indicated that the temperature, dissolved phosphates concentration, ammonium nitrogen and pH were the main determining factors of the phytoplankton community dynamics. During the study, 13 coda dominated the phytoplankton biomass. Cyanobacteria of the codon H1 with such species as Aphanizomenon gracile, Dolichospermum planctonicum, D. viguieri dominated the phytoplankton community before restoration. S1 group consisting of Planktolyngbya limnetica, Limnothrix redekei and Planktothrix agardhii mostly dominated during the period in which the first method was used. Improvement of water quality due to restoration efforts in the third period caused dominance of other groups, especially J (Actinastrum hantzschii and other Chlorococcales), C (Asterionella formosa and other diatoms), Y (Cryptomonas marssonii and other cryptophytes), Lo (Peridiniopsis cunningtonii and other dinophytes) and X2 (Rhodomonas lacustris).

Adsorption Ability of Cephalexin onto the Straw-Based Activated Carbon: Performance and Mechanism

A straw-activated carbon has been successfully synthesized with the high BET surface area, at 494.9240 m2/g, which is perfectly suitable for the adsorption of cephalexin antibiotic from aqueous water. It is noted that the adsorption capacity of straw-activated carbon is demonstrated by the effect of initial concentration, contact time, pH solution and dosage. The straw-activated carbon exhibited improved decontaminant efficiency towards cephalexin antibiotics. Quick and improved sorption could be attributable to the distinctive structural and compositional merits as well as the synergetic contribution of functional groups to surface material. Most interestingly, the adsorption capacity achieved at pH 6 was ~98.52%. A mechanism adsorption has been proposed to demonstrate adsorption of the straw-activated carbon (AC-S). By comparison with other studies, it is confirmed that AC-S in this study obtained a higher removal efficiency than other adsorbent materials, suggesting that straw-activated carbon may be an appropriate candidate to treat cephalexin from wastewater media

Carbonate budgets as indicators of functional reef “health”: A critical review of data underpinning census-based methods and current knowledge gaps

• Calcium carbonate budgets as indicators for reef health are understudied. • Geographic gaps exist in the Coral Triangle and Southwestern Pacific. • Further studies are necessary across reef zones and depth, and over time. • Paucity of supporting data on calcification and erosion constrains budget estimates. • Future research to increase spatial coverage and study environmental change impacts. The carbonate budget of a reef describes the net rate of carbonate production resulting from various biologically-, physically- and chemically-driven production and erosion processes. Thus, budget state metrics can provide important information on a reef’s growth potential and on the capacity of reefs to sustain key geo-ecological services such as habitat provision and coastal protection. Whilst various approaches for estimating carbonate budgets exist, census-based methods have gained recent interest because they quantify the contribution of different functional groups and taxa, and allow assessments of the links between changing reef ecology and budget states. However, the present paucity of supporting data on growth and erosion rates for the majority of coral species and reef-associated taxa represents a constraint on these budget estimates and limits meaningful between-site comparisons. In light of the growing interest in using carbonate budgets as a functional reef “health” assessment tool, this review thus considers our current state of knowledge regarding the geographic coverage of existing reef budget states and the availability of relevant supporting data. We use this to highlight current knowledge gaps, future challenges, and opportunities that emerging techniques may offer. The primary aim of this review is to encourage increased research efforts on budget states and underlying metrics in order to better constrain reef carbonate budget estimates from across a broad range of sites and environments.

Hemoglobin self-assembly and antibacterial activities of bio-modified Ag-MgO nanocomposites by different concentrations of Artemisia haussknechtii and Protoparmeliopsis muralis extracts

Interaction of metal nanoparticles and metal nanocomposites with blood proteins is important from the perspectives of cytotoxicity and production of novel drug delivery systems. In this study, Ag-MgO nanocomposites were bio-modified by different concentrations of Artemisia haussknechtii medicinal plant and Protoparmeliopsis muralis medicinal lichen extracts. Determination of physicochemical properties of NCs were carried out by UV–Visible spectroscopy, scanning electron microscope (SEM), X-ray powder diffraction (XRD), and Fourier transform infrared (FT‐IR) analyses. Antibacterial effects of NCs against methicillin-resistant Staphylococcus aureus (MRSA), E. coli ATCC 25922, and P. aeruginosa ATCC 27853 bacteria were measured by disc diffusion and minimum inhibition/bactericidal concentrations (MIC and MBC). Also, in final section, interaction of bio-modified NCs (BNCs) with hemoglobin (Hb) protein was surveyed by SEM, atomic force microscope (AFM), and FT‐IR techniques. BNCs by plant extract (10%w/v) showed highest antibacterial effects on E. coli ATCC 25922 as inhibition zone diameter of (IZD) value of 20 ± 0.89 mm. Aggregation of Hb around BNCs was approved by mentioned analyses. This investigation illustrated contribution of various functional groups including thiol and imidazole groups in self-assembly of Hb surrounding BNCs.

Uranium biosorption mechanism model of protonated Saccharomyces cerevisiae

Further understanding absorption uranium mechanism of the regenerational biosorbent is very interesting in application of the biosorbent. The regeneration adsorbent of Saccharomyces cerevisiae biomass was made by hydrochloric acid. Using it to absorb uranium at low constant pH(2.50), accompanied with proton releasing the ratio almost 1:2 which is to be analyzed in this paper. The type and amount of functional groups in the biomass such as carboxyl, amino, phosphoryl were determined by Potentiometric titrations and FTIR analysis. Chemical modification showed that the contribution of functional groups to uranium adsorption was carboxyl, phosphoryl and amino in turn. Analysis of SEM-EDX and staining microscopy showed that uranium on the surface of cells did not exist in the form of precipitation at lower pH 2.98, but at higher pH 4.52. The effects of phosphorus release and pH on uranium species was analyzed by MINTEQ software 3.0. Based on the above boundary conditions of the model construction, a multi-site of functional groups model equation of ion exchange absorption mechanism was built in which the final uranium ion concentration and pH as functions. It could well describe the exchange equilibrium of proton with uranium ion at pH2.50 to pH4.00.

Effect of carboxyl and hydroxyl groups on adsorptive polysaccharide fouling: A comparative study based on PVDF and graphene oxide (GO) modified PVDF surfaces

We investigated the contribution of different functional groups on polysaccharides to membrane fouling. To achieve so, we examined the adsorption of two typical polysaccharides, i.e., glucan (only –OH) and sodium alginate (enriched –COOH) on surfaces of PVDF membranes with and without graphene oxide (GO) modification. The results suggest that the interaction between carboxyl groups and Ca2+ significantly altered the particle size and charge of sodium alginate. Resultantly, the irreversible fouling of PVDF membrane surface caused by polysaccharide (i.e., sodium alginate) adsorption became more reversible when the concentration of Ca2+ exceeded a critical value. In comparison, glucan containing only hydroxyl groups exhibited unidirectional increase in irreversible fouling along with the increased Ca2+ concentration. Modification of PVDF membrane using GO did alleviate adsorptive fouling, but the Ca2+ bridging between the modified membrane surface and sodium alginate makes the fouling less reversible. Therefore, foulant property and water chemistry should be taken in to account in evaluating the performance of membrane hydrophilization using GO.

Exploration of icariin analog structure space reveals key features driving potent inhibition of human phosphodiesterase-5.

The natural product icariin inhibits human phosphodiesterase-5 (PDE5) and represents a unique pharmacophore for treating erectile dysfunction, pulmonary hypertension, and other diseases. In this study, we explore the available icariin-derived chemical scaffolds through medicinal chemistry to develop novel icariin PDE5 inhibitors with improved potency and specificity. We synthesized six novel semi-synthetic icariin analogs as well as three naturally occurring icariin analogs, and characterized the structure-activity relationship in the context of human PDE5 inhibition using in vitro enzyme inhibition and kinetics assays and molecular modeling. Mammalian-cell-based assays and in vitro enzyme inhibition assays against human PDE6C further helped to identify the most potent and selective icariin analogs. Our results reveal the synergistic contribution of functional groups at the C3 and C7 positions of the icariin backbone towards PDE5 inhibition. Whereas a hydrophobic and flexible alkanol group at the C7 position is sufficient to enhance icariin analog potency, combining this group with a hydrophilic sugar group at the C3 position leads to further enhancement of potency and promotes specificity towards PDE5 versus PDE6C. In particular, compounds 3 and 7 exhibit Ki values of 0.036 ± 0.005 μM and 0.036 ± 0.007 μM towards PDE5 respectively, which are approaching those of commercial PDE5 inhibitors, and can effectively reduce GMP levels in cultured human BJ-hTERT cells. This study identifies novel icariin analogs as potent and selective PDE5 inhibitors poised to become lead compounds for further pharmaceutical development.

Study on the rejuvenating mechanism in aged asphalt binder with mono-component modified rejuvenators

The roads’ renovation and reconstruction not only requires a lot of economics, but also causes serious environmental problems. Preventive maintenance has significant economic and environmental benefits. Therefore, as an effective preventive maintenance material, rejuvenator has received extensive attention from researchers in the past three decades. However, there is few concerns about single component’s impact on the regeneration effect of aged asphalt. In this study, four kinds of mono-component modifiers including ethanol, acetaldehyde, ethylenediamine and acetone was used to prepare mono-component modified rejuvenators. The regeneration effect of mono-component modified rejuvenators was then characterized and compared by fundamental physical properties and viscoelastic properties to study the effective contributions of different chemical functional groups on regenerative process of aged asphalt. The results show that the change of asphalt properties caused by aging and regeneration differ obviously depending on the type of aged binder and mono-component. Therefore, it is necessary to examine the aging degree and conditions of asphalt material, in the case where it is considered to use rejuvenators to maintain the asphalt pavement, thereby selecting the types of rejuvenator material accordingly.

Binding of Sulfoxaflor to Aplysia californica-AChBP: Computational Insights from Multiscale Approaches.

Structural features and binding properties of sulfoxaflor (SFX) with Ac-AChBP, the surrogate of the insect nAChR ligand binding domain (LBD), are reported herein using various complementary molecular modeling approaches (QM, molecular docking, molecular dynamics, and QM/QM'). The different SFX stereoisomers show distinct behaviors in terms of binding and interactions with Ac-AChBP. Molecular docking and Molecular Dynamics (MD) simulations highlight the specific intermolecular contacts involved in the binding of the different SFX isomers and the relative contribution of the SFX functional groups. QM/QM' calculations provide further insights and a significant refinement of the geometric and energetic contributions of the various residues leading to a preference for the SS and RR stereoisomers. Notable differences in terms of binding interactions are pointed out for the four stereoisomers. The results point out the induced fit of the Ac-AChBP binding site according to the SFX stereoisomer. In this process, the water molecules-mediated contacts play a key role, their energetic contribution being among the most important for the various stereoisomers. In all cases, the interaction with Trp147 is the major binding component, through CH···π and π···π interactions. This study provides a rationale for the binding of SFX to insect nAChR, in particular with respect to the new class of sulfoximine-based insect nAChR competitive modulators, and points out the requirements of various levels of theory for an accurate description of ligand-receptor interactions.