Density Functional Complexation Study of Metal Ions with Cysteine

Abstract

Metal complexes of cysteine have been studied using a density functional theory based method together with a continuum solvation model. Complexation geometries for metal complexes of cysteine with Zn(2+), Mg(2+), Ca(2+), Fe(3+), and Mn(2+) have been determined. Different coordination modes have been considered for MCys(2) and MCys(3) complexes. Complexation energies have been determined, and they have been corrected with (empirical) metal- and ligand-specific parameters, the latter of which was determined separately for Cys(N,O,S) and Cys(N,S) ligands. The results indicate that the preferred binding mode for Zn(2+) with cysteine is bidentate (N,S) type binding in tetrahedral or trigonal bipyramidal geometry while Mg(2+) and Ca(2+) prefer sulfur-free binding sites in octahedral geometry. Fe(3+) prefers binding via sulfur and nitrogen atoms, whereas for Mn(2+) several equally stable structures were found. The new correction parameters can be applied for other sulfur-containing ligands to evaluate the binding strength of a new ligand with metal ions. The observed preferences of metal ions in binding are in agreement with the previous knowledge of the behavior of metal ions.

Theoretical Study of the Interaction of 1,2-Dithiolene Ligands with the Mg2+ and Ca2+ Aquacations: Electronic, Geometric and Energetic Analysis

“…Several studies report this methodology to determine the strength of binding of metal cations and ligands. [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][38][39][40][41][42][43][44][45][46][47] …”

“…It was found that the peripheral groups bonded to the anchoring atom that binds to the metal cation modulate the interaction strength. Pesonen et al 35 performed a density functional theory (DFT) study of the interaction of mono-and bidentate ligands with metal cations, where the interaction with the bidentate ligands was stronger than that with monodentate ones. The size of the cation, its softness and the stabilization energy of ligand's chelation directly affected the coordination preferences.…”

“…21 The interaction between divalent metal cations and organic ligands was analyzed in a large number of studies. [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] The interaction of alkaline earth metal cations with Oand N-coordinating ligands was quantified by binding energies, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies and energy gap values as well as metal-ligand bond length, and ligand-to-metal electronic donation. It was seen that the O-coordinating ligands have the largest affinity for those cations.…”

Reactivity of polynuclear zinc‐thiolate sites

“…This functional has been shown to give reasonable optimized ZnAS and ZnAN bond lengths in numerous studies of zinc complexes [49][50][51][52]. In order to speed up the calculations, the multipole accelerated resolution of identity for J (MARI-J) approximation method [53], as implemented in Turbomole [54], has been used.…”

O-Phenylenediamine-Cysteine Nanosphere Having Conjugated Structures: A Highly Selective Fluorescent Probe for Mercury Ion

“…The low-molecular-weight thiols, such as L-cysteine (L-Cys), homocysteine (Hcy), and glutathione (GSH), which play important roles in many physiological and biochemical application [36]. L-Cys molecule contains a -SH which makes it unique among the amino acids [37]. So we want to synthesize a material containing -SH for detection of metal ions based on above reasons.…”