Binding Energies Of Complexes Research Articles

An Efficient Implementation of the Nwat-MMGBSA Method to Rescore Docking Results in Medium-Throughput Virtual Screenings.

Nwat-MMGBSA is a variant of MM-PB/GBSA based on the inclusion of a number of explicit water molecules that are the closest to the ligand in each frame of a molecular dynamics trajectory. This method demonstrated improved correlations between calculated and experimental binding energies in both protein-protein interactions and ligand-receptor complexes, in comparison to the standard MM-GBSA. A protocol optimization, aimed to maximize efficacy and efficiency, is discussed here considering penicillopepsin, HIV1-protease, and BCL-XL as test cases. Calculations were performed in triplicates on both classic HPC environments and on standard workstations equipped by a GPU card, evidencing no statistical differences in the results. No relevant differences in correlation to experiments were also observed when performing Nwat-MMGBSA calculations on 4 or 1 ns long trajectories. A fully automatic workflow for structure-based virtual screening, performing from library set-up to docking and Nwat-MMGBSA rescoring, has then been developed. The protocol has been tested against no rescoring or standard MM-GBSA rescoring within a retrospective virtual screening of inhibitors of AmpC β-lactamase and of the Rac1-Tiam1 protein-protein interaction. In both cases, Nwat-MMGBSA rescoring provided a statistically significant increase in the ROC AUCs of between 20 and 30%, compared to docking scoring or to standard MM-GBSA rescoring.

Hydrogen and Halogen Bonding in Cyclic FH(4- n):FCl n Complexes, for n = 0-4.

Ab initio MP2/aug'-cc-pVTZ calculations have been carried out to investigate the six unique cyclic quaternary complexes FH:FH:FH:FH, FH:FH:FH:FCl, FH:FH:FCl:FCl, FH:FCl:FH:FCl, FH:FCl:FCl:FCl, and FCl:FCl:FCl:FCl stabilized by F-H···F hydrogen bonds and F-Cl···F halogen bonds. The binding energies of these complexes decrease as the number of FH molecules decreases, and therefore as the number of hydrogen bonds decreases, indicating that hydrogen bonds are primarily responsible for stabilities. Nonadditivities of binding energies are synergistic for complexes with 4, 3, and 2 FH molecules, but antagonistic for those with 1 and 0 FH molecules. In addition to depending on changes in F-F, F-H, and F-Cl distances, complex binding energies are also influenced by two sets of angular parameters. These include the external F-F-F angles which must sum to 360° in these cyclic structures, and the internal H-F-F angles for hydrogen bonds and F-Cl-F angles for halogen bonds, which measure the deviation from linearity of these bonds. Transition structures present the barriers to converting an equilibrium structure to an equivalent equilibrium structure on the potential surfaces. These barriers increase as the number of FH molecules decreases. EOM-CCSD spin-spin coupling constants 2h J(F-F) across hydrogen bonds in complexes tend to increase with decreasing F-F distance. They increase dramatically in transition structures, but show no dependence on the F-F distance. The one-bond coupling constants 1h J(F-H) are relatively small and negative in complexes, increase dramatically, and are positive in transition structures. 1 J(F-H) values are greatest for the covalent F-H bond. Coupling constants 1x J(F-Cl) across halogen bonds are relatively small and positive in complexes, and increase dramatically in transition structures. The largest values of 1 J(F-Cl) are found for covalent bonds.

Influence of Photoisomerization on Binding Energy and Conformation of Azobenzene-Containing Host-Guest Complex

Influence of Photoisomerization on Binding Energy and Conformation of Azobenzene-Containing Host-Guest Complex

Azines as Electron-Pair Donors to CO2 for N···C Tetrel Bonds.

Ab initio MP2/aug'-cc-pVTZ calculations were performed to investigate tetrel-bonded complexes formed between CO2 and the aromatic bases pyridine, the diazines, triazines, tetrazines, and pentazine. Of the 23 unique equilibrium azine:CO2 complexes, 14 have planar structures in which a single nitrogen atom is an electron-pair donor to the carbon of the CO2 molecule, and 9 have perpendicular structures in which two adjacent nitrogen atoms donate electrons to CO2, with bond formation occurring along an N-N bond. The binding energies of these complexes vary from 13 to 20 kJ mol-1 and decrease as the number of nitrogen atoms in the ring increases. For a given base, planar structures have larger binding energies than perpendicular structures. The binding energies of the planar complexes also tend to increase as the distance across the tetrel bond decreases. Charge transfer in the planar pyridine:CO2 complex occurs from the N lone pair to a virtual nonbonding orbital of the CO2 carbon atom. In the remaining planar complexes, charge transfer occurs from an N lone pair to the remote in-plane π*C-O orbital. In perpendicular complexes, charge transfer occurs from an N-N bond to the adjacent π*O-C-O orbital of CO2. Decreases in the bending frequency of the CO2 molecule and in the 13C chemical shielding of the C atom of CO2 upon complex formation are larger in planar structures compared to perpendicular structures. EOM-CCSD spin-spin coupling constants 1tJ(N-C) for complexes with planar structures are very small but still correlate with the N-C distance across the tetrel bond.

Intermolecular hydrogen bonds between 1,4-benzoquinones and HF molecule: Synergetic effects, reduction potentials and electron affinities

Some biological activities of quinones can be attributed to the H-bonding ability of acceptor oxygen atoms. According to the results obtained from the quantum mechanical calculations performed on a wide variety of complexes between the 1,4-benzoquinone (BQ) derivatives and HF molecules, the interplay between H-bonds and individual H-bond interaction energies (EHB) can be affected by the substituents placed on the six-membered ring of BQ. The total binding energies of complexes become more negative by the electron donating substituents (EDSs) while the changes are reversed by the electron withdrawing substituents (EWSs). The mutual interplay between the X-BQ⋯(HF)n (n=1–3) interactions has been investigated using the geometrical parameters, synergetic energies (SE) and the EHB values. Hydrogen bonding decreases the reduction potentials (E0red) and increases the electron affinities (EA) of X-BQ derivatives. Linear relationships have been observed between the E0red (and EA) values and the Hammett constants of substituents.

Direct observation of giant binding energy modulation of exciton complexes in monolayer MoSe2

Screening due to the surrounding dielectric medium reshapes the electron-hole interaction potential and plays a pivotal role in deciding the binding energies of strongly bound exciton complexes in quantum confined monolayers of transition metal dichalcogenides (TMDs). However, owing to strong quasiparticle band-gap renormalization in such systems, a direct quantification of estimated shifts in binding energy in different dielectric media remains elusive using optical studies. In this work, by changing the dielectric environment, we show a conspicuous photoluminescence peak shift at low temperature for higher energy excitons $(2s,3s,4s,5s)$ in monolayer $\mathrm{MoS}{\mathrm{e}}_{2}$, while the $1s$ exciton peak position remains unaltered -- a direct evidence of varying compensation between screening induced exciton binding energy modulation and quasiparticle band-gap renormalization. The estimated modulation of binding energy for the $1s$ exciton is found to be $58.6%$ $(72.8%$ for $2s,75.85%$ for $3s$, and $85.6%$ for $4s)$ by coating an $\mathrm{A}{\mathrm{l}}_{2}{\mathrm{O}}_{3}$ layer on top, while the corresponding reduction in quasiparticle band-gap is estimated to be 246 meV. Such direct evidence of large tunability of the binding energy of exciton complexes as well as the band-gap in monolayer TMDs holds promise of novel device applications.

INSILICO STUDIES OF OXIME PRODRUG OF GLICLAZIDE AGAINST SULPHONYLUREA RECEPTORS (SUR 1)

Objective: Objective of the study is to perform a molecular docking analysis of novel oxime prodrug of gliclazide against SUR1 receptor.Methods: Sulfonylurea receptors (SUR) are membrane proteins which are the molecular targets of the sulfonylurea class of anti-diabetic drugs whose mechanism of action is to promote insulin release from pancreatic beta cells. Oxime prodrug of gliclazide a better soluble derivative of gliclazide is used for enhancement of bioavailability of gliclazide. Autodock 4.2 software was used for docking studies. Ligand 2D structures were drawn using ChemDraw Ultra 7.0. Binding sites, docking poses and interactions of the ligand with SUR1 receptors were studied by pymol software.Results: The docking studies suggest that potential binding sites of oxime prodrug of gliclazide exhibiting all the major interactions such as hydrogen bonding, hydrophobic interaction and electrostatic interaction with GLU43, LEU11, LEU 40, ILE17 GLU 68, GLN72 residues of SUR1. The binding energy of complexes are also found to be minimal forming stable complexes.Conclusion: In silico study of oxime prodrug of gliclazide conforms, the binding of oxime prodrug of glicalzide with SUR1 receptors which effectively controls the release insulin to regulate plasma glucose concentrations. Hence, the oxime prodrug of gliclazide could be a potent anti-diabetic target molecule which may be worth for further in vitro and in vivostudies.

Etoposide and doxorubicin enhance the sensitivity of triple negative breast cancers through modulation of TRAIL-DR5 axis.

Death receptor 5 (DR5) is an important target for development of anticancer agents against triple-negative breast cancer (TNBC). Recently, we reported the molecular level details for the modulation of TRAIL-DR5 axis by quinacrine (QC) in breast cancer cells. In this work, the DR5 mediated anticancer potential of topoisomerase inhibitor etoposide (ET) and doxorubicin (DOX) against TNBC has been evaluated. ET and DOX enhanced the DR5 expression in TNBC cells, whereas non-topoisomerase inhibitors pifithrin-α (PIF) and dexamethasone (DEX) failed to do so. In the TRAIL pre-treated cells, ET and DOX induced higher apoptosis, indicating their synergistic effect with TRAIL. The molecular docking and molecular dynamics studies showed their ability to stabilize the TRAIL-DR5 complex, whereas PIF and DEX failed to do so. The binding energy for TRAIL-DR5 complexation in the ternary complexes containing ET (-111.08kcal/mol) and DOX (-76.35kcal/mol) were higher than reported binding energy of binary complex (-53.70kcal/mol). The in silico and in vitro mutational studies highlighted the importance of DR5 residue SerB68 in mediating the receptor-drug interaction. ET and DOX failed to enhance apoptosis in DR5 knockdown (DR5-KD) cells. On the other hand, TRAIL+ET exhibited induction of DR5 and subsequent apoptosis in WT-DR5 overexpressed DR5-KD cells, by modulating the mitochondrial intrinsic apoptosis cascade. An induction of apoptosis and DR5 expression was noticed in xenograft mice and in TNBC patient-derived metastatic cells after TRAIL+ET treatment. Thus, data suggests ET and DOX act as DR5 agonistic ligands and enhance the cellular apoptosis in TNBC.

Using the multi-objective optimization replica exchange Monte Carlo enhanced sampling method for protein\u2013small molecule docking

BackgroundIn this study, we extended the replica exchange Monte Carlo (REMC) sampling method to protein–small molecule docking conformational prediction using RosettaLigand. In contrast to the traditional Monte Carlo (MC) and REMC sampling methods, these methods use multi-objective optimization Pareto front information to facilitate the selection of replicas for exchange.ResultsThe Pareto front information generated to select lower energy conformations as representative conformation structure replicas can facilitate the convergence of the available conformational space, including available near-native structures. Furthermore, our approach directly provides min-min scenario Pareto optimal solutions, as well as a hybrid of the min-min and max-min scenario Pareto optimal solutions with lower energy conformations for use as structure templates in the REMC sampling method. These methods were validated based on a thorough analysis of a benchmark data set containing 16 benchmark test cases. An in-depth comparison between MC, REMC, multi-objective optimization-REMC (MO-REMC), and hybrid MO-REMC (HMO-REMC) sampling methods was performed to illustrate the differences between the four conformational search strategies.ConclusionsOur findings demonstrate that the MO-REMC and HMO-REMC conformational sampling methods are powerful approaches for obtaining protein–small molecule docking conformational predictions based on the binding energy of complexes in RosettaLigand.

Behavior of uncharged oximes compared to HI6 and 2-PAM in the human AChE-tabun conjugate: a molecular modeling approach

Tabun is one of the most dangerous nerve agents because it has deleterious effects like inhibition of the essential enzymes acetylcholinesterase (AChE) and butyrylcholinesterase. Some oximes such HI6 as 2-PAM are nucleophiles that are capable to reactivate inhibited human AChE under some conditions. Zwitterionic and cationic species have the best chance of productive action on inhibited AChE. However uncharged oximes can give important interaction information. In order to investigate the interaction and behavior of cationic and uncharged oximes, we performed molecular docking simulations and molecular dynamics and calculated binding energies of complexes of these compounds with human AChE. The uncharged oximes of larger structure were more susceptible to the influence of the substituents on the phosphorus atom and presented low binding energies. In contrast, HI 6 and 2-PAM showed high binding energy values with great contribution of the amino acid Asp74, demonstrating the importance of the quaternary nitrogen to the affinity and interaction of the oximes/AChE tabun-inhibited complexes.

Interaction of Ti and Cr atoms with point defects in bcc vanadium: A DFT study

The development of low-swelling radiation-resistant alloys is vital for the creation of reliable fusion reactors. In this article, we revisit the long-standing problem of very low radiation swelling in V-Ti-Cr alloys by means of DFT calculations. In particular, we study double and triple interactions of point defects such as solutes, vacancies and self-interstitial atoms in bcc V. According to our results titanium atom and vacancy are strongly attracted and in addition to pairs form highly stable triple Ti-Vacancy-Ti complexes, which are absent in the case of chromium. By using an analytic model of void growth and using calculated binding energies of point defect complexes in bcc vanadium we obtain three orders of magnitude reduction of swelling rate due to the formation of Ti-Vacancy-Ti complexes, which allows to explain experimental observations. Finally, we explain the causes of the strong attraction between titanium and vacancy using geometry and electronic structure analysis.

IN SILICO STUDY OF CRYO-EM STRUCTURES OF ANTIGEN-ANTIBODY COMPLEX OF CHIKUNGUNYA FOR THE DEVELOPMENT OF DIAGNOSTIC AGENT

Objective: Despite the availability of the commercial rapid tests of chikungunya, the difference of pathogen’s genotypes amongst different countries has created some causes for concern. It is found that the sensitivity of the current chikungunya rapid tests on Asian strain was only 20.5%, as compared to 90.3% when tested on the African phylogroup. Therefore, the development of diagnostics that is specific for the current strain circulating in the country is important to be done. The cryo-electron microscopy (cryo-EM) structures of antigen-antibody complex can be used as an insightful structural basis to the development of the tailored antibody for diagnostics purposes. However, cryo-EM structures usually were resolved in low resolution, thus some sterical clashes between residues are expected. This work aims to refine the cryo-EM structures of E1 E2 of chikungunya virus (CHIKV) in complex with antibody using molecular mechanics method, to calculate the binding energy of antigen-antibody complex, and to compare it with the experimental results.Methods: Thecryo-EM structures were refined in vacuoby short minimization scheme using AMBER 14. The binding energies were calculated using Firedock and MM/GBSA methods.Results:The results showed that the direct calculation of binding energies of cryo-EM structures reflected high repulsive forces. While the calculation on the refined structured showed lower binding energies. Visual inspections on the complex structures also indicated that the refined structures showed better interactions.Conclusion:As a conclusion, the refinement of cryo-EM structures should be useful to gain more insight into the binding mode of interactions between antigenic protein and antibody, at the atomic level.

Excitonic complexes in GaN/(Al,Ga)N quantum dots

Here we report a theoretical investigation of excitonic complexes in polar GaN/(Al,Ga)N quantum dots (QDs). A sum rule between the binding energies of charged excitons is used to calculate the biexciton binding energy. The binding energies of excitonic complexes in GaN/AlN are shown to be strongly correlated to the QD size. Due to the large hole localization, the positively charged exciton energy is found to be always blueshifted compared to the exciton one. The negatively charged exciton and the biexciton energy can be blueshifted or redshifted according to the QD size. Increasing the size of GaN/AlN QDs makes the identification of charged excitons difficult, and the use of an Al0.5Ga0.5N barrier can be advantageous for clear identification. Our theoretical results for the binding energy of exciton complexes are also confronted with values deduced experimentally for InAs/GaAs QDs, confirming our theoretical prediction for charged excitonic complexes in GaN/(Al,Ga)N QDs. Finally, we realize that the trends of excitonic complexes in QDs are significantly related to competition between the local charge separation (whatever its origin) and the correlation effect. Following our findings, entangled photons pairs can be produced in QDs with careful control of their size in order to obtain zero exciton–biexciton energy separation.

All-Atom Four-Body Knowledge-Based Statistical Potentials to Distinguish Native Protein Structures from Nonnative Folds.

Recent advances in understanding protein folding have benefitted from coarse-grained representations of protein structures. Empirical energy functions derived from these techniques occasionally succeed in distinguishing native structures from their corresponding ensembles of nonnative folds or decoys which display varying degrees of structural dissimilarity to the native proteins. Here we utilized atomic coordinates of single protein chains, comprising a large diverse training set, to develop and evaluate twelve all-atom four-body statistical potentials obtained by exploring alternative values for a pair of inherent parameters. Delaunay tessellation was performed on the atomic coordinates of each protein to objectively identify all quadruplets of interacting atoms, and atomic potentials were generated via statistical analysis of the data and implementation of the inverted Boltzmann principle. Our potentials were evaluated using benchmarking datasets from Decoys-‘R'-Us, and comparisons were made with twelve other physics- and knowledge-based potentials. Ranking 3rd, our best potential tied CHARMM19 and surpassed AMBER force field potentials. We illustrate how a generalized version of our potential can be used to empirically calculate binding energies for target-ligand complexes, using HIV-1 protease-inhibitor complexes for a practical application. The combined results suggest an accurate and efficient atomic four-body statistical potential for protein structure prediction and assessment.

Theoretical Study of the Gaseous Hydrolysis of NO2 in the Presence of Amines.

The effects on the hydrolysis of NO2 in the presence of methylamine and dimethylamine molecules were investigated by theoretical calculations of a series of the molecular clusters 2NO2-mH2O-CH3NH2 (m = 1-3) and 2NO2-mH2O-(CH3)2NH (m = 1, 2). With methylamine included in the clusters, the energy barrier is reduced by 3.2 kcal/mol from that with ammonia, and the corresponding products may form without an energy barrier. The results show that amines have larger effects than ammonia in promoting the hydrolysis of NO2 on thermodynamics. The additional water molecules can stabilize the transition states and the product complexes, and we infer that adding more water molecules in the reactions mainly act as solvent and promoting to form the methylamine nitrate (CH3NH3+NO3-). In addition, the interactions of CH3NH2 and (CH3)2NH on the hydration of HNO3 are also more effective than NH3, and the NH4NO3, CH3NH3NO3, and (CH3)2NH2NO3 complexes tend to form the larger aerosols with the increasing of water molecules. The equilibrium geometries, harmonic vibrational frequencies, and intensities of both HONO-CH3NH2 and HONO-NH3 complexes were investigated. Calculations predict that the binding energies of both HONO-CH3NH2 complexes are larger than HONO-NH3 complexes, and the OH stretching vibrational frequencies and intensities are most affected. The natural bond orbital analysis was performed to describe the donor-acceptor interactions on a series of complexes in the reactions 2NO2 + H2O + CH3NH2 and 2NO2 + H2O + (CH3)2NH, as well as the complexes of HONO-NH3 and HONO-CH3NH2. The results show that the interactions with amines are relatively larger, and the higher stabilization energies between CH3NH2 and HONO are found.

Pyridyl-indolizine derivatives as DNA binders and pH-sensitive fluorescent dyes

New fluorescent anthracene-based indolizine derivative has been synthesized by appendix of the anthracene moiety via “click” chemistry at the first position of indolizinic core. The new product has been carefully characterized and its absorption-emission properties studied in aqueous buffer solutions at different pH values and also compared to its precursor containing only pyridyl-indolizinic core. The anthracenemodified indolizine and its precursor were tested for DNA binding using agarose gel electrophoresis, UV–vis and fluorescence experiments. The comparative experimental data were in accordance to the molecular docking simulation of the corresponding systems using the Yassara computer program. Both experimental and simulation results suggest that the anthracene-modified indolizine has a superior affinity for the DNA than its precursor due to much lower values of binding energy and dissociation constant of the corresponding complex.

Potential mesogens based on pyridine derivatives: The geometric structure, conformational properties and characteristics of intermolecular hydrogen bonds

Conformational properties of the main part (excluding OC3H7 radicals) of the p-n-propyloxybenzoic (A1) and p-n-propyloxycinnamic (A2) acids molecules (relating to mesomorphic compounds) as well as p-n-propyloxybenzoic acid pyridine ester (B1) and p-n-propyloxyphenylazopyridine (B2) molecules (relating to non-mesomorphic compounds) were studied by DFT(B3LYP)/cc-pVTZ method. It was shown that the main parts of A1 and A2 acids are rigid. The barrier to internal rotation of pyridine fragment in the B1 and B2 molecules depends on the nature of the bridging group. It was determined that all studied A1⋯B1, A2⋯B1 and A2⋯B2 complexes are characterized by a strong hydrogen bond. The binding energy of complexes (≈14 kcal/mol, with BSSE corrections, DFT(B97D)/6-311++G**) exceeds the energy per hydrogen bond in the corresponding acid dimers (≈10 kcal/mol). The structural non-rigidity of A⋯B complexes is mainly caused by possibility of OC3H7 radicals internal rotation and A and B molecules rotation about the (H)O⋯N line. The characteristics of intermolecular hydrogen bonds were determined by NBO-analysis. The obtained results indicate that examined complexes correspond to the basic requirements to mesogen molecular forms. The thermodynamic functions of the gas-phase complexation reactions (idealized model of the complexes formation in the condensed state) were calculated. Preliminary studies of mesogen–non-mesogen A1⋯B2 system by differential scanning calorimetry and polarizing optical microscopy, showed that it has mesomorphic properties.

Computational Study of the Interactions between Benzene and Crystalline Ice Ih : Ground and Excited States.

Ground-state geometries of benzene on crystalline ice cluster model surfaces (Ih ) are investigated. It is found that the binding energies of benzene-bound ice complexes are sensitive to the dangling features of the binding sites. We used time-dependent DFT to study the UV spectroscopy of benzene, ice clusters, and benzene-ice complexes, by employing the M06-2X functional. It is observed that the size of the ice cluster and the dangling features have minor effects on the UV spectral characteristics. Benzene-mediated electronic excitations of water towards longer wavelengths (above 170 nm) are noted in benzene-bound ice clusters, where the cross-section of photon absorption by water is negligible, in good agreement with recent experimental results (Thrower et al., J. Vac. Sci. Technol. A, 2008, 26, 919-924). The intensities of peaks associated with water excitations in benzene-ice complexes are found to be higher than in isolated ice clusters. The π→π* electronic transition of benzene in benzene-ice complexes undergoes a small redshift compared with the isolated benzene molecule, and this holds for all benzene-bound ice complexes.

Application of Genetic Programming (GP) Formalism for Building Disease Predictive Models from Protein-Protein Interactions (PPI) Data.

Protein-protein interactions (PPIs) play a vital role in the biological processes involved in the cell functions and disease pathways. The experimental methods known to predict PPIs require tremendous efforts and the results are often hindered by the presence of a large number of false positives. Herein, we demonstrate the use of a new Genetic Programming (GP) based Symbolic Regression (SR) approach for predicting PPIs related to a disease. In a case study, a dataset consisting of one hundred and thirty five PPI complexes related to cancer was used to construct a generic PPI predicting model with good PPI prediction accuracy and generalization ability. A high correlation coefficient(CC) of 0.893, low root mean square error (RMSE) and mean absolute percentage error (MAPE) values of 478.221 and 0.239, respectively were achieved for both the training and test set outputs. To validate the discriminatory nature of the model, it was applied on a dataset of diabetes complexes where it yielded significantly low CC values. Thus, the GP model developed here serves a dual purpose: (a)a predictor of the binding energy of cancer related PPI complexes, and (b)a classifier for discriminating PPI complexes related to cancer from those of other diseases.

Potential role of selected antiepileptics used in neuropathic pain as human GABA transporter isoform 1 (GAT1) inhibitors—Molecular docking and pharmacodynamic studies

The chemical interaction of nine antiepileptic drugs (tiagabine, gabapentin, pregabalin, lamotrigine, zonisamide, valproic acid, valpromide, vigabatrin, progabide) and two endogenous metabolites (4-aminobutanoic acid, 4-hydroxybutanoic acid) with a model of human GABA transporter 1 (hGAT1) is described using the molecular docking method. To establish the role of hGAT1 in chronic pain, tiagabine, a selective hGAT1 inhibitor, was assessed in the in vivo experiments for its antiallodynic properties in two mouse models of neuropathic pain. Docking analyses performed in this study provided the complex binding energies, specific hydrogen bond components, and hydrogen bond properties such as energies, distances and angles. The data of the docking studies strongly support the assumption that the antiepileptic and analgesic actions of the studied drugs can be at least in part related to the strength of their chemical interactions with hGAT1. In vivo experiments with tiagabine confirmed the involvement of hGAT1 in the regulation of the mechanical nociceptive threshold in neuropathic pain.