Cd2+-induced conformational change of a synthetic metallopeptide: slow metal binding followed by a slower conformational change.
A two-stranded alpha-helical coiled coil was prepared having a Cys 4 metal-binding site within its hydrophobic interior. The addition of Cd2+ results in the incorporation of 2 equiv of metal ion, which is accompanied by a conformational change of the peptide, as observed by circular dichroism (CD) spectroscopy. Isothermal titration calorimetry (ITC) shows that the addition of Cd2+ is accompanied by two thermodynamic events. A comparison of the time dependence of the ITC behavior with those of the UV absorption and CD behavior allows the assignment of these events to a preliminary endothermic metal-binding step followed by a slower exothermic conformational change.
Mukherjee
Madhumita
M
Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
Zhu
Xianchun
X
Ogawa
Michael Y
MY
D000595:Amino Acid Sequence; D002104:Cadmium / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D002151:Calorimetry; D002942:Circular Dichroism; D006358:Hot Temperature; D007700:Kinetics; D008667:Metalloproteins / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary / Q000187:drug effects; D013997:Time Factors
D008667:Metalloproteins; D010455:Peptides; D002104:Cadmium