Comparison of Cysteine and Penicillamine Ligands in a Co(II) Maquette
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- 作者：Amy K. Petros ; Sarah E. Shaner ; Alison L. Costello ; David L. Tierney ; and Brian R. Gibney
- 刊名：Inorganic Chemistry
- 出版年：2004
- 出版时间：August 9, 2004
- 年：2004
- 卷：43
- 期：16
- 页码：4793 - 4795
- 全文大小：83K
- 年卷期：v.43,no.16(August 9, 2004)
- ISSN：1520-510X
文摘
L-Penicillamine (Pen) has been investigated as a ligand formetalloprotein design by examining the binding of Co(II) to thesequence NH2-KL(Pen)EGG·(Pen)IG(Pen)GA(Pen)·GGW-CONH2.For comparison, we have studied Co(II) binding to the analogoussequence with Cys ligands, the ferredoxin maquette ligand IGAthat was originally designed to bind a [4Fe-4S] cluster. The Co(II)affinity and UV-vis spectroscopic properties of IGA indicateformation of a pseudotetrahedral tetrathiolate ligated Co(II). Incontrast, IGA-Pen showed formation of a pseudotetrahedralcomplex with Co(II) bound by three Pen ligands and an exogenousH2O. EXAFS data on both Co(II) complexes confirms not only theproposed primary coordination spheres but also shows six Co(II)-C
methyl group distances in Co(II)-IGA-Pen. These resultsdemonstrate that ligand sterics in simple peptides can be designedto provide asymmetric coordination spheres such as thosecommonly observed in natural metalloproteins.
methyl group distances in Co(II)-IGA-Pen. These resultsdemonstrate that ligand sterics in simple peptides can be designedto provide asymmetric coordination spheres such as thosecommonly observed in natural metalloproteins.