TY - JOUR
T1 - ZnII and HgII binding to a designed peptide that accommodates different coordination geometries
AU - Szunyogh, Dániel
AU - Gyurcsik, Béla
AU - Larsen, Flemming Hofmann
AU - Stachura, Monika
AU - Thulstrup, Peter Waaben
AU - Hemmingsen, Lars Bo Stegeager
AU - Jancsó, Attila
PY - 2015/7/28
Y1 - 2015/7/28
N2 - Designed metal ion binding peptides offer a variety of applications in both basic science as model systems of more complex metalloproteins, and in biotechnology, e.g. in bioremediation of toxic metal ions, biomining or as artificial enzymes. In this work a peptide (HS: Ac-SCHGDQGSDCSI-NH2) has been specifically designed for binding of both ZnII and HgII, i.e. metal ions with different preferences in terms of coordination number, coordination geometry, and to some extent ligand composition. It is demonstrated that HS accommodates both metal ions, and the first coordination sphere, metal ion exchange between peptides, and speciation are characterized as a function of pH using UV-absorption-, synchrotron radiation CD-, 1H-NMR-, and PAC-spectroscopy as well as potentiometry. HgII binds to the peptide with very high affinity in a {HgS2} coordination geometry, bringing together the two cysteinates close to each end of the peptide in a loop structure. Despite the high affinity, HgII is kinetically labile, exchanging between peptides on the subsecond timescale, as indicated by line broadening in 1H-NMR. The ZnII-HS system displays more complex speciation, involving monomeric species with coordinating cysteinates, histidine, and a solvent water molecule, as well as HS-ZnII-HS complexes. In summary, the HS peptide displays conformational flexibility, contains many typical metal ion binding groups, and is able to accommodate metal ions with different structural and ligand preferences with high affinity. As such, the HS peptide may be a scaffold offering binding of a variety of metal ions, and potentially serve for metal ion sequestration in biotechnological applications.
AB - Designed metal ion binding peptides offer a variety of applications in both basic science as model systems of more complex metalloproteins, and in biotechnology, e.g. in bioremediation of toxic metal ions, biomining or as artificial enzymes. In this work a peptide (HS: Ac-SCHGDQGSDCSI-NH2) has been specifically designed for binding of both ZnII and HgII, i.e. metal ions with different preferences in terms of coordination number, coordination geometry, and to some extent ligand composition. It is demonstrated that HS accommodates both metal ions, and the first coordination sphere, metal ion exchange between peptides, and speciation are characterized as a function of pH using UV-absorption-, synchrotron radiation CD-, 1H-NMR-, and PAC-spectroscopy as well as potentiometry. HgII binds to the peptide with very high affinity in a {HgS2} coordination geometry, bringing together the two cysteinates close to each end of the peptide in a loop structure. Despite the high affinity, HgII is kinetically labile, exchanging between peptides on the subsecond timescale, as indicated by line broadening in 1H-NMR. The ZnII-HS system displays more complex speciation, involving monomeric species with coordinating cysteinates, histidine, and a solvent water molecule, as well as HS-ZnII-HS complexes. In summary, the HS peptide displays conformational flexibility, contains many typical metal ion binding groups, and is able to accommodate metal ions with different structural and ligand preferences with high affinity. As such, the HS peptide may be a scaffold offering binding of a variety of metal ions, and potentially serve for metal ion sequestration in biotechnological applications.
U2 - 10.1039/c5dt00945f
DO - 10.1039/c5dt00945f
M3 - Journal article
C2 - 26040991
SN - 1477-9226
VL - 44
SP - 12576
EP - 12588
JO - Dalton Transactions (Print Edition)
JF - Dalton Transactions (Print Edition)
ER -