A detailed kinetic analysis of metal encapsulation by a de novo-designed protein is described. The kinetic mechanism of Hg(II) encapsulation in the three-stranded coiled coil formed by the peptide CH(3)CO-G LKALEEK CKALEEK LKALEEK G-NH(2) (Baby L9C) is derived by global analysis. The mechanism involves rapid initial collapse of two peptides by Hg(II) forming Hg(Baby L9C(-H))(2) with a linear th...