Coordination and binding properties of zwitterionic glutathione with transition metal cations

详细信息	查看全文 | 推荐本文 |

• 作者：R. Shankar^a ; P. Kolandaivel^b ; ^{ponkvel@hotmail.com} ; L. Senthil kumar^b
• 关键词：Glutathione ; Zwitterion ; Transition metal cations ; DFT ; Atomic charge ; Metal ion affinity
• 刊名：Inorganica Chimica Acta
• 出版年：2012
• 期刊代码：40_00201693
• 类别：ch
• 出版时间：30 May, 2012
• 卷：387
• 期：Complete
• 页码：125-136
• 文件大小：2802 K

摘要

The interaction of metal cations at different nucleophilic sites of zwitterionic forms of glutathione complexes (Glu-A, Glu-B)-M²⁺ were studied using the hybrid density functional theory (DFT-B3LYP) and second order Moller-plesset perturbation theory (MP2) methods. The metal ions coordinate with glutathione complexes in tri and tetra dentate manner. The zwitterionic forms of glutathione (Glu-A) and (Glu-B) are found to be neutralized during interaction with transition metal cations in the gas phase. The tetrahedral or square pyramidal with multi membered chelating ring complexes and higher coordination numbers quite favors for stabilizing the Cd²⁺, Hg²⁺ and Zn²⁺ metal cations in Glu-A-M²⁺ and Glu-B-M²⁺ complexes to form the most stable complexes. The overall structural parameters of zwitterionic forms of glutathione (GSH) complexes are not altered by metal ion substitution; however the metal ion binding site has undergone a noticeable change. The metal ion affinity and basis set superposition error (BSSE) corrected interaction energy was computed for all the complexes. The stability orders of the zwitterionic form of glutathione complexes remain the same in relative energy, interaction energy and metal ion affinity (MIA) values. Solvent effects, with explicit water molecules and polarizable continuum model (PCM), were considered to study the most stable Cd²⁺, Hg²⁺ and Zn²⁺ complexes.