Chemistry Reference
In-Depth Information
of peptide-based biomimetic materials, and it remains to be seen how cells respond to
the new type of peptide-based scaffold.
Attempts to control fiber lateral aggregation have also been made by several other
groups through rational design of coiled coil peptides. For instance, Potekhin et al.
(2001) reported on the design of an a-helical fibril-forming peptide (aFFP) that was
formulated into a coiled coil pentamer (Fig. 14.2) where the interhelical ionic forces
between residues at the f and g positions were highlighted. In contrast, in a coiled
coil dimer and trimer, such salt bridges cannot be formed because of the different
geometry presented by the self-assembled coiled coils. The structural model proposed
in Figure 14.2 accounts for the formation of a staggered coiled coil pentamer.
The number of helix strands within a coiled coil is determined by the axial shift
made by neighboring helices and the total length of an individual peptide.
The staggered pattern, unlike the design in the SAF peptides modulated by the side
chain interaction, was created because of the identical heptad repeats along the entire
peptide that tends to form offsets within the multistranded coiled coil assembly.
The resultant structure with overhanging ends presents the hydrophobic amino
Figure 14.2 (a) Representation of a two-dimensional five-stranded coiled coil assembly with
one heptad unit shifting in the axial direction with respect to each other and (b) the correspond-
ing structural model. (c) Illustration of a three-dimensional model with nonheptad units over-
hanging in the peripheral region showing the structural tolerance of noncoiled coil fragments.
Reprinted from Potekhin et al. (2001). Copyright 2001 Cell Press.
