Characterization of the Metal Binding Properties of De Novo Designed Coiled Coil Metalloproteins
The dissertation aims to elucidate three effects on the metal binding properties of
de novo designed coiled coil metalloproteins, which are the stability of the
peptide,the placement of the metal binding motif along the peptide sequence, and the variationof the metal binding motif.
Starting from a previously designed peptide C16C19-GGY, a more stable peptide
was designed. The new peptide is AQC16C19-GGY. Its Cd(II) complex is a trimer
containing 4 Cd(II). In contrast, the Cd(II) complex of C16C19-GGY is a dimer with
one Cd(II). The process of the incorporation of Cd(II) into AQC16C19-GGY is shown
to be a fast bond formation process followed by a slow conformation change.
Therefore, the stability of the peptide affects the metal binding properties.
The effect of the placement of the metal binding motif along the peptide
sequence on the metal binding properties was demonstrated by a series of peptides
derived from the parent peptide: K(IEALEGK)4GGY. The peptides are C2C5-GGY,
C9C12-GGY, C16C19-GGY (the previously studied one), and C23C26-GGY. The
Cu(I) binding properties of these peptides were studied and compared. C2C5-GGY
and C9C12-GGY have similar metal binding properties. C23C26-GGY has different
metal binding properties from those of C2C5-GGY and C9C12-GGY, but its metal
binding properties are similar to those of C16C19-GGY. The placement of the metal
binding motif along the peptide sequence also plays a role in determining the
oligomerization states of the metalloproteins.
In the last chapter, the C-X-X-C metal binding motif was changed to C-X-X-H to
study the effect of the first coordination sphere on the metal binding properties. It is seen that the first coordination sphere has an effect on the metal binding properties.Interestingly, one of the obtained metalloproteins shows pH-dependent luminescence properties.
School:Bowling Green State University
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:de novo design metalloproteins metal binding cu i
Date of Publication:01/01/2009