Interaction of Li+, Na+, and K+ with the Proline Amino Acid. Complexation Modes, Potential Energy Profiles, and Metal Ion Affinities

Inducing high exo selectivity in Diels-Alder reaction by dimethylborane substituent: a DFT study

In this work, the role of Lewis acid-base (LAB) interaction on the stereoselectivity of the Diels-Alder (DA) reaction has been studied by DFT in gas and solution (dichloromethane) phases. The calculations were performed at the B3LYP/6-311G++ (d, p) level. Two different series of DA reactions were investigated: (1)-three mono-substituted cyclopentadienes + dimethyl(vinyl)borane; (2)-five α,β-unsaturated carbonyl compounds + cyclopenta-2,4-dien-1-yldimethylborane. The reacting diene and dienophile pairs were chosen to restrict LAB interaction to the exo reaction pathway. It was found that in some of the examined cases, the favorable LAB interaction is so strong that it can lead to a completely exo-selective DA reaction. Furthermore, a novel multistep synthetic method was hypothesized for preparing exo cycloadduct with near 100% stereoselectivity. Our results can open up new avenues toward the rational design of exo-selective DA reactions for synthesizing novel bioorganic compounds.

Interaction of Cysteine with Li+ and LiF in the Presence of (H2O) n (n = 0-6) Clusters

The interaction between cysteine with Li⁺ and LiF in the microcosmic water environment was investigated to elucidate how ions interact with amino acids and the cation-anion correlation effect involved. The structures of Cys·Li⁺(H₂O) _n and Cys·LiF(H₂O) _n (n = 0-6) were characterized using ab initio calculations. Our studies show that the water preferentially interacts with Li⁺/LiF. In Cys·Li⁺(H₂O)_0-6, Li⁺ interacts with amino nitrogen, carbonyl oxygen, and hydrophobic sulfur of Cys to form a tridentate mode, whereas in Cys·LiF(H₂O) _n , Li⁺ and F^- work in cooperation and interact with carbonyl oxygen and hydroxyl hydrogen of Cys to form a bidentate type. The neutral and zwitterionic forms are essentially isoenergetic when the water number reaches three in the presence of Li⁺, whereas this occurs at four water molecules in the presence of LiF. Further research revealed that the interaction between Li⁺/LiF and Cys was mainly electrostatic, followed by dispersion, and the weakest interaction occurs at the transition from the neutral form to zwitterionic form. Natural population analysis charge analyses show that for Cys·Li⁺(H₂O) _n , the positive charge is mostly concentrated on Li⁺ except for the system containing three water molecules. For Cys·LiF(H₂O) _n , the positive charge is centered on the LiF unit in the range n = 0-6, and at n = 5, electron transfer from Cys to water occurs. Our study shows that the contribution of anions in zwitterionic state stabilization should be addressed more generally along with cations.

A TD-DFT study of the excited dissociative electronic states of the DNA nucleobases bound to Li. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021;244:118862. [PMID: 32927359 DOI: 10.1016/j.saa.2020.118862]

In this work, the first and second dissociative potential curves of adenineLi⁺ (ADLi⁺), guanineLi⁺ (GUALi⁺), cytosineLi⁺(CYTLi⁺), and thymineLi⁺ (THYLi⁺) complexes, related to the dissociation of their LiO and LiN bonds, have been calculated in the gas phase and water, separately. For this purpose, the fifteen excited potential curves, in order of increasing energy, were calculated for each complex and the dissociative potential curves were distinguished from them considering the conical intersection points. The time-dependent density functional theory (TD-DFT) method employing the M06-2X functional was used for the calculations. It was observed that the electron transfer from the DNA base to the Li⁺ took place during the dissociation of complexes in the gas phase. The electrostatic field of water blocked this charge transfer and led to the excited DNA base and Li⁺ in its ground state. The vertical excitation energy for the desorption of the Li fragment as a neutral and cation species from the DNA bases was determined. The effect of the interaction site of Li⁺ on the dissociative potential curves was also investigated.

Theoretical investigation of the effect of hydrogen bonding on the stereoselectivity of the Diels–Alder reaction

Here, we report the computational prediction of high exo selectivities in a series of Diels–Alder reactions with H-bonding interaction.

Comparison of acidity and metal ion affinity of D-Glucosamine and N-acetyl-D-glucosamine, a DFT study

The derivatives of glucose such as glucosamine (β-D-GlcN) and N-acetyl-D-β-glucosamine (GlcNAc) are significant in several biological systems. D-GlcN has been used widely to treat osteoarthritis in humans and animal models as well as GlcNAc has been proposed as a treatment for autoimmune diseases. The DFT/B3LYP/6-311++G (d,p) method as well as QTAIM and NBO analyses were used to the acidity values of D-GlcN and GlcNAc sugars and their complexes with alkali ions in the gas phase. The Li⁺, Na⁺ and K⁺ prefer bi-dentate chelate in these complexes. The computed results indicate that metal ion affinity (MIA) in GlcNAc is higher than that in D-GlcN. There are direct correlations between the MIA values of D-GlcN and GlcNAc sugars and the atomic numbers of Li, Na, and K. The calculated acidity values for GlcNAc at C₂-NH and C₆-HO₆ sites are 331 and 333 kcal mol^-1, respectively. Whereas the calculated acidity values for D-GlcN at C₂-NH and C₆-HO₆ sites are 365 and 372 kcal mol^-1, respectively. The AIM and NBO analyses indicate the presence of intramolecular H-bonds in GlcNAc sugar in both its neutral form and conjugate base; whereas D-GlcN indicates intramolecular H-bonds in only its conjugate base.

Label-free colorimetric detection of serum cysteine using Ag-NP probes in the presence of Be2+ ions

Amino acids play a crucial role in a variety of significant metabolic processes and their homeostasis is essential for cell growth and survival.

Modeling of neotame and fructose thermochemistry: Comparison with mono and divalent metal ions by Computational and experimental approach

The metal complexes can demonstrate various interesting biological activities in the human body. However, the role of certain metal ions for specific cell activities is still subject to debate. This study is aimed at comparing the thermochemical properties of neotame (artificial sweetener) and α, β-fructose in gas phase and water medium. The interaction of α and β-fructose, neotame with monovalent and divalent metal ions was studied and comprehended by density functional theory (DFT) using B3LYP functional, 6–311 + G (d, p) and D3 basis set. Metal ion affinities (MIA) values depicted that ionic radius of metal ions played an important role in the interaction of α, β-fructose and neotame. The ∆G parameter was calculated to predict and understand the interaction of metal ions with α and β-fructose, neotame. The results suggested that the presence of hydroxyl groups and oxygen atoms in sugar molecules acted as preferred sites for the binding and interaction of mono and divalent ions. For the first time computational study has been introduced in the present study to review the progress in the application of metal binding with sugar molecules especially with neotame. Moreover, voltammetric behaviour of neotame-Zn²⁺ was studied using cyclic and differential pulse voltammetry. The obtained results suggest that the peak at −1.13 V is due to the reduction of Zn²⁺ in 0.1 M phosphate buffer medium at pH 5.5. Whereas, addition of 6-fold higher concentration of neotame to the ZnCl₂.2H₂O resulted in a new irreversible cathodic peak at −0.83, due to the reduction of neotame-Zn²⁺ complex. The Fourier transform infrared spectroscopy (FTIR) results indicates that the β-amino group (-NH) and carboxyl carbonyl (-C = O) groups of neotame is participating in the chelation process, which is further supported by DFT studies. The findings of this study identify the efficient chelation factors as major contributors into metal ion affinities, with promising possibilities to determine important biological processes in cell wall and glucose transmembrane transport.

A mechanism of alkali metal carbonates catalysing the synthesis of β-hydroxyethyl sulfide with mercaptan and ethylene carbonate

The reaction of β-hydroxyethylation is essential to the current practice of organic chemistry. Here, we proposed a new and green route to synthesize 2-hydroxyethyl n-alkyl sulfide with n-alkyl mercaptan and ethylene carbonate (EC) in the presence of alkali carbonates as catalysts and revealed the mechanism by experiments and theoretical calculations. The reaction reported proceeds rapidly with high yields when it is performed at 120 °C and the catalytic loading is ∼1 mol%. This protocol is applicable to other mercaptans to synthesize the corresponding β-hydroxyethyl sulfide. Density functional theory-based calculations show the energy profile for the reaction pathway. The rate-determining step is the ring-opening of EC. A negatively charged O atom of alkali carbonates approaches the S atom of -SH under the influence of hydrogen bonds. An activated S atom that carries more negative charge serves as a nucleophilic reagent and assists in the ring-opening of EC by reducing the Mayer bond orders of the C1-O1 bond in EC. Alkali cations also contribute to the C1-O1 bond cleavage. The energy barrier for the ring-opening of EC decreases with the decrease of electronegativity of alkali cations. Subsequent transference of a H atom leads to the formation of β-hydroxyethyl sulfide, the dissociation of CO2 and the reduction of K2CO3.

Evidence for cooperative Na+ and Cl− binding by strongly hydrated l-proline

Strongly hydrated l-proline cooperatively binds Na⁺ and Cl⁻ ions in aqueous solution.

Interaction of l-proline with group IIB (Zn2+, Cd2+, Hg2+) metal cations in the gas and aqueous phases: a quantum computational study

The gas and aqueous phase complexation geometries, electronic interactions, and metal ion affinities of Zn2+, Cd2+, and Hg2+ metal cations with the two most stable conformations of l-proline complexes were studied. The complexes were optimized by density functional theory (B3LYP) using the 6-311++G(d,p) orbital basis set and relativistic pseudopotentials for the metal cations. The interactions of the metal cations at different nucleophilic sites of l-proline were considered as were three modes of interactions including salt bridged, charge solvated 1, and charge solvated 2, which are indicative of binding in a bidentate manner through the carboxylate group, carbonyl and hydroxyl oxygen, and carbonyl oxygen and the nitrogen atom of l-proline. All of the coordination patterns were characterized by both charge transfer and ionic interactions between l-proline and the metal cation. The metal ion affinity (MIA) and interaction energy were also computed for all of the complexes at both the gas and aqueous phases. Results showed that the order of MIA at the gas and aqueous phases are different. MIA order at the gas phase was in the order of Zn2+ > Hg2+ > Cd2+ whereas at the aqueous phase, the order of Zn2+ > Cd2+ > Hg2+ was obtained for MIA. The infrared stretching vibrational modes of the N–H and O–H groups of free l-proline were compared with l-proline–M2+ in both CS1 and CS2 coordination patterns at the gas phase and results showed a considerable shift to lower frequency during complexation process.

An insight into the interaction of L-proline with the transition metal cations Fe(2+), Co(2+), Ni(2+): a gas phase theoretical study

The interaction of Fe(2+), Co(2+), and Ni(2+) with L-proline has been studied. Three modes of interaction have been considered: salt bridged (SB), involving binding in a bi-dentate manner through the carboxylate group of L-proline, charge solvated 1 (CS1) involving carbonyl and hydroxyl oxygen, and charge solvated 2 (CS2) involving carbonyl oxygen and the lone pair of the nitrogen atom. All calculations including geometry optimization, metal ion affinities (MIAs), and frequency calculations of the binding structures of Fe(2+), Co(2+), and Ni(2+) to L-proline were calculated using the hybrid density functional theory (DFT-B3LYP) method. All three cations were found to bind preferentially in a zwitterionic (SB) coordination pattern with the metal ion affinity in the order Ni(2+) ˃ Co(2+) ˃ Fe(2+) in all binding forms. The nature of the binding interaction between metal cations and L-proline was found to be mainly electrostatic. Comparison of the infrared vibrations of the C=O, the N-H and the O-H groups of free L-proline with L-proline-M(2+) in both CS1 and CS2 complex structures indicated a considerable shift to lower frequency during complexation. In order to gain more insight into the nature of the interaction of L-proline with group VIIIB metal ions, comparison of the interaction of L-proline with other cations such as (Li(+), Na(+), K(+), Be(2+), Mg(2+), and Ca(2+)) was made. Graphical Abstract L-proline with the transition metal cations Fe(2+), Co(2+), Ni(2.)

An insight into hydration structure of sodium glycinate from ab initio quantum chemical study

The hydration structure of sodium glycinate (Na(+)GL(-)) is probed by the Monte-Carlo multiple minimum (MCMM) method combined with quantum mechanical (QM) calculations at the MP2/6-311++G(d,p) level. In the gas phase, the energy of [Na(+)GL(-)]β is more than 30 kJ mol(-1) higher than [Na(+)GL(-)]α. With higher degrees of hydration, our results indicate that the most stable conformers of [Na(+)GL(-)]∙(H2O)8 were derived from [Na(+)GL(-)]β instead of [Na(+)GL(-)]α. The stable conformers determined by the conductor-like polarizable continuum model (CPCM) also show that [Na(+)GL(-)]β is more stable than [Na(+)GL(-)]α in the liquid phase. By analyzing the hydration process, water…water hydrogen bonding interaction will be more preferable than ion…water interaction as the number of water molecules increases. According to the electronic density at the bond critical point on the Na-X bonds (X = O1, O2, N) in the low-energy conformers, Na(+)GL(-) will be dissociated as Na(+) and GL(-) in the bulk water, which is not predicted by the CPCM model. The structure features and the charge redistribution of Na(+)GL(-) will provide a physical explanation for the weakening Na-O1 interaction.

The protonated and sodiated dimers of proline studied by IRMPD spectroscopy in the N-H and O-H stretching region and computational methods

IRMPD spectroscopy and computational chemistry techniques have been used to determine that the proton- and sodium-bound dimers of proline exist as a mixture of a number of different structures. Simulated annealing computations were found to be helpful in determining the unique structures of the protonated and sodiated dimers, augmenting chemical intuition. The experimental and computational results are consistent with the proton-bound dimer of N-protonated proline bound to zwitterionic proline. There was no spectroscopic evidence in the 3200-3800 cm(-1) region for a canonical structure which is predicted to have a weak N-H stretch at about 3440 cm(-1). A well resolved band at 1733 cm(-1) from a previous spectroscopic study (DOI: 10.1021/ja068715a ) was reassigned from a high energy canonical isomer to the C=O stretch of a lower energy zwitterionic structure. This band is a free carboxylate C=O stretch where protonated proline is hydrogen bonded to the other carboxylate oxygen which is also involved in an intramolecular hydrogen bond. Fifteen structures of the sodium bound proline dimer were computed to be within 10 kJ mol(-1) of Gibbs energy and eight structures were within 5 kJ mol(-1). None of these structures can be ruled out based on the experimental IRMPD spectrum. They all have an N-H stretching band predicted in a position that agrees with the experimental spectrum. However, only structures where one of the proline monomers is in the canonical form and having a free O-H bond can produce the band at ∼3600 cm(-1).

The mechanisms of α-H and proton transfers of glycine induced by Mg2+

A MP2/6-31++G(d,p)//B3LYP/6-31++G(d,p) method was used to investigate the mechanisms of α- H and proton transfers of glycine induced by Mg 2+. Eight complexes were obtained, six of which were neutral and the other two were zwitterionic. Among them, the zwitterion with a binding energy of 159.4 kcal/mol was the most stable structure. Conformation transformations of the complexes caused by the rotation of single bond and the transfers of α- H and proton were completed via seven transition states. The inductive effect of Mg 2+ made the electron cloud of glycine deviate to Mg 2+, which activated the covalent bond involving the transferred proton. The neutral complex can be turned into the zwitterionic one by the transfers of both carboxyl hydrogen and α- H , and the energy barrier of each reaction was less than 9.2 kcal/mol. After the transfer of α- H , a delocalized π bond was formed in glycine skeleton and the α- C atom took 0.19 positive charges. So the chemical activity of the glycine enhanced, and glycine was readily available for addition and nucleophilic substitution reactions. The path from the most stable glycine conformer G1 to the zwitterionic conformation I is G1 → G1–G3 → G3 → G3–G4 → G4 → G2–G4 → G2 → VI → I–VI → I, and the highest energy barrier of this path is 9.2 kcal/mol.

Complexation of some alkali and alkaline earth metal cations by macrocyclic compounds containing four pyridine subunits – a DFT study

Tetradentate pyridine-based macrocyclic compounds offer useful ligands capable of efficient and selective complexation of M = Li⁺, Na⁺, K⁺, Be²⁺, Mg²⁺and Ca²⁺.

Discrimination of 4-hydroxyproline diastereomers by vibrational spectroscopy of the gaseous protonated species

Hydroxylation of proline is a prominent oxidative post-translational modification (oxPTM) in animals, characterized by site specificity and stereochemical control. The presence of this irreversible modification and the ensuing generation of a chiral center have been assayed in (2S,4R)-4-hydroxyproline and (2S,4S)-4-hydroxyproline forming the protonated species by electrospray ionization and sampling them by infrared multiple photon dissociation (IRMPD) spectroscopy. IRMPD spectra, recorded both in the 950-1950 cm(-1) (using the CLIO free electron laser) and in the 3200-3700 cm(-1) [using a tabletop parametric oscillator/amplifier (OPO/OPA) laser] regions, have been interpreted by comparison with the absorbance spectra of the lowest energy structures calculated at MP2/6-311+G** level of theory. Remarkable spectral differences have emerged in the fingerprint region, pointing to the unambiguous discrimination between S,R and S,S diastereomers. The main differences arise from the position of the carbonyl stretching mode, a signature of nonzwitterionic structures, moving from 1750 cm(-1) for the S,R form to 1770 cm(-1) for the S,S diastereomer. Furthermore, a well-defined band associated with the NH(2) wagging mode at 1333 cm(-1) is a distinct mark of the S,S isomer. Each gaseous protonated epimer comprises a population of at least three conformers, stabilized by intramolecular hydrogen bonds linking the two hydrogens of protonated secondary amine group with the 4-hydroxy substituent and with an oxygen atom of the carboxylic group, respectively. Interestingly, a tendency to adopt either C(4)-exo (up) or C(4)-endo (down) pyrrolidine puckering upon proline 4(R)- or 4(S)-hydroxylation, respectively, is observed here. The same bias is found in neutral hydroxyprolines and in collagen model peptides. In the protonated species under examination, this bias originates chirality-induced vibrational features revealed by IRMPD spectroscopy.

Molecular dynamics studies of β-hairpin folding with the presence of the sodium ion

Metal ions are ubiquitous in protein systems and play a significant role during their folding processes. Nineteen independent structures were determined for the Na(+)/β-hairpin interacting systems, and their folding pathways are different. (i) For Na(S47), the turn is rapidly shaped with the help of Na(+) and acts as the folding nucleus for the rest regions. Two intermediate states are observed and the resulted structure is the most folded. (ii) For Na(B41), Na(B52), Na(B54), Na(S55) and Na(B56), the inclusive Na(+) ions are anchored by β-strands. The local structures around the Na(+) ions and the turn regions fold simultaneously and serve as two independent folding nuclei. (iii) The other systems have no folding nuclei and correspond to low-folded structures. Long-range electrostatic interactions contribute a lot to the folding, especially from the four negatively charged residues (Glu42, Asp46, Asp47 and Glu56). The initial positions of the Na(+) ions are largely responsible for the different folding behaviors. The interactions with sidechain- rather than backbone-O atoms generally lead to more compact structures. Another factor affecting the folding is whether the O atoms are associated with native H-bonds, and those involved show decreased affinities to metal ions. The addition of water solvent does not induce obvious folding and conformational transitions to the Na(+)/β-hairpin interacting systems.

DFT STUDY OF BOND ENERGIES AND ATTACHMENT SITES OF SAMPLE DIVALENT CATIONS (Mg2+, Ca2+, Zn2+) TO HISTIDINE IN THE GAS PHASE

In view of better understanding interactions of amino acids and peptides with metallic cations in the isolated state, the model system histidine– M 2+ ( M 2+ = Mg 2+, Ca 2+, Zn 2+) has been studied theoretically. The computations have been performed with the help of the density functional theory (DFT) and the B3LYP functional. The extended basis set was the standard 6-311++G**. All the molecular complexes obtained by the interaction between several energetically low-lying tautomers/conformers/zwitterions of histidine and the cations on different binding sites were considered.

Our study shows that complexes of histidine with Mg 2+, Ca 2+, Zn 2+ are rather similar. In the isolated state, the most stable form corresponds to a tridentate complex in which the cation interacts with oxygen and two nitrogen atoms: one from the terminal NH 2 and one from the imidazole ring. All computations indicate that the metal ion affinity (MIA) decreases on going from Zn 2+ to Mg 2+ and Ca 2+, for the considered amino acid. This indicates that histidine prefers to bind to the transition metal cation rather than alkali earth metals. The influence of theses cations on the acidity of histidine were also considered. As expected, upon metal complexation, proton dissociation of histidine becomes much more favorable, that is, its acidity becomes much less endothermic.

DFT STUDY ON GAS-PHASE INTERACTION BETWEEN HISTIDINE AND ALKALI METAL IONS (Li+, Na+, K+); AND INFLUENCE OF THESE IONS ON HISTIDINE ACIDITY

The gas-phase metal affinities of histidine Li +, Na + and K + ions have been determined theoretically employing the hybrid B3LYP exchange–correlation functional and using 6-311++G** basis sets. All computations indicate that the metal ion affinity decreases on going from Li + to Na + and K + for the considered amino acid. Different types of M + coordinations on several histidine conformers/tautomers were considered in detail.

The optimized structures indicate that Li + and Na + prefer a tri-dentate coordination, bonding with a nitrogen atom of imidazole ring ( N τ), – NH 2, and an oxygen atom of a carbonyl, while in the K +-histidine lowest-energy conformer, the cation appears to be bi-coordinated to both oxygen atoms of the zwitterionic form by the energy values not too far from that of tri-coordination. We also performed the DFT calculations for proton dissociation energy of histidine both in the presence and absence of alkali metal ions. Our results also reveal that the acidity of histidine dramatically increases upon metal ion complexation.

A proline-based neuraminidase inhibitor: DFT studies on the zwitterion conformation, stability and formation

The designs of potent neuraminidase (NA) inhibitors are an efficient way to deal with the recent "2009 H1N1" influenza epidemic. In this work, density functional calculations were employed to study the conformation, stability and formation of the zwitterions of 5-[(1R,2S)-1-(acetylamino)-2-methoxy-2-methylpentyl]-4-[(1Z)-1-propenyl]-(4S,5R)-d-proline (BL), a proline-based NA inhibitor. Compared to proline, the zwitterion stability of BL is enhanced by 1.76 kcal mol(-1) due to the introduction of functional groups. However, the zwitterion of BL will not represent a local minimum on the potential energy surface until the number of water molecules increases up to two (n = 2). With the addition of two and three water molecules, the energy differences between the zwitterions and corresponding canonical isomers were calculated at 3.13 and -1.54 kcal mol(-1), respectively. The zwitterions of BL are mainly stabilized by the H-bonds with the water molecules, especially in the case of three water molecules where the carboxyl-O atoms are largely coordination-saturated by three H-bonds of medium strengths, causing the zwitterion stability even superior to the canonical isomer. With the presence of two and three water molecules, the energy barriers for the conversion processes from the canonical isomers to the zwitterions are equal to 4.96 and 3.13 kcal mol(-1), respectively. It indicated that the zwitterion formation is facile to take place with addition of two molecules and further facilitated by more water molecules. Besides, the zwitterion formation of BL is finished in a single step, different from other NA inhibitors. Owing to the above advantages, BL is a good NA inhibitor candidate and more attention should be paid to explorations of BL-based drugs.

Structures, energetics, and dynamics of gas phase ions studied by FTICR and HPMS

Both Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and high-pressure mass spectrometry (HPMS) are very powerful tools in the field of gas phase ion chemistry. Many experimental method developments based on FTICR-MS and HPMS are summarized, including the coupling of a high-pressure external ion source to a FTICR mass spectrometer, blackbody infrared radiative dissociation (BIRD), coupling laser desorption ionization with HPMS, infrared multiple photon dissociation (IRMPD), radiative association and bimolecular routes to gas phase cluster ion formation. An abundance of thermochemical data, such as proton affinities, gas phase acidities, methyl cation affinities and metal cation affinities, have been obtained. Some of these data are the basis of the standard data listed in the NIST thermochemical databases. Ion-molecule interactions, energetics, reactivities, and structures of molecules have been extensively investigated using the methods developed based on HPMS and FTICR mass spectrometric techniques.

Conformational analysis of alkali metal complexes of anionic species of aspartic acid, their interconversion and deprotonation: A DFT investigation

Gas-phase geometry-optimized structures of aspartate complexes of anionic species (Hasp(-)) with lithium, sodium and potassium metal cations and transition-state structures for their interconversions were obtained using the density functional theory computations at the B3LYP/6-311++G(d,p) level of theory. The metal ion affinities of Hasp(-) species and deprotonation energies of [Hasp-M] complexes, M=Li+, Na+ and K+, and their conformers were obtained. Relative energies of the [Hasp-M] complex conformers, reaction energies, thermodynamic properties, rate and equilibrium constants of their complexation are reported. Binding energies of the most stable complexes with Li+, Na+ and K+ are -168.53, -133.34 and -117.68kcal/mol, respectively. The most stable complex conformer as a tri-coordinated form for aspartate complex with Li(+) and bi-coordinated form for aspartate complexes with Na+ and K+ were found.