10.1021/ic0497679.s001
Amy K. Petros
Amy K.
Petros
Sarah E. Shaner
Sarah E.
Shaner
Alison L. Costello
Alison L.
Costello
David L. Tierney
David L.
Tierney
Brian R. Gibney
Brian R.
Gibney
Comparison of Cysteine and Penicillamine Ligands in a Co(II) Maquette
American Chemical Society
2004
EXAFS
coordination spheres
NH
ferredoxin maquette ligand IGA
Co
exogenous H 2 O
UV
KL
2004-08-09 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Comparison_of_Cysteine_and_Penicillamine_Ligands_in_a_Co_II_Maquette/3329455
l-Penicillamine (Pen) has been investigated as a ligand for
metalloprotein design by examining the binding of Co(II) to the
sequence NH<sub>2</sub>−KL(Pen)EGG·(Pen)<b>IG</b>(Pen)G<b>A</b>(Pen)·GGW−CONH<sub>2</sub>.
For comparison, we have studied Co(II) binding to the analogous
sequence with Cys ligands, the ferredoxin maquette ligand <b>IGA</b>
that was originally designed to bind a [4Fe-4S] cluster. The Co(II)
affinity and UV−vis spectroscopic properties of <b>IGA</b> indicate
formation of a pseudotetrahedral tetrathiolate ligated Co(II). In
contrast, <b>IGA-Pen</b> showed formation of a pseudotetrahedral
complex with Co(II) bound by three Pen ligands and an exogenous
H<sub>2</sub>O. EXAFS data on both Co(II) complexes confirms not only the
proposed primary coordination spheres but also shows six Co(II)-C<sub>β</sub> methyl group distances in Co(II)-<b>IGA-Pen</b>. These results
demonstrate that ligand sterics in simple peptides can be designed
to provide asymmetric coordination spheres such as those
commonly observed in natural metalloproteins.