Chemistry Faculty Publications

Document Type

Article

Abstract

AQ-Pal14 is a 30-residue polypeptide that was designed to form an alpha-helical coiled coil that contains a metal-binding 4-pyridylalanine residue on its solvent-exposed surface. However, characterization of this peptide shows that it exists as a three-stranded coiled coil, not a two-stranded one as predicted from its design. Reaction with cobalt(III) protoporphyrin IX (Co-PPIX) produces a six-coordinate Co-PPIX(AQ-Pal 14)(2) species that creates two coiled-coil oligomerization domains Coordinated to opposite laces of the porphyrin ring. It is found that this species undergoes a buffer-dependent Self-assembly process: nanometer-scale globular materials were formed when these components were reacted in unbuffered H(2)O, while millimeter-scale, rod-like materials were prepared when the reaction was performed in phosphate buffer (20 mM, pH 7). It is suggested that assembly of the globular material is dictated by the conformational properties of the coiled-coil forming AQ-Pal14 peptide, whereas that a the rod-like material involves interactions between Co-PPIX and phosphate ion.

Publication Date

10-2010

Publication Title

Biomacromolecules

Volume

11

Issue

10

Start Page No.

2602

End Page No.

2609

DOI

10.1021/bm100540t

Included in

Chemistry Commons

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