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Modular Supramolecular Biomaterials Based on a Coiled-Coil Scaffold

Oshaben, Kaylyn (2016) Modular Supramolecular Biomaterials Based on a Coiled-Coil Scaffold. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Abstract

Nature uses proteins and nucleic acids to form a wide array of structural motifs. Chemists have applied these motifs to the rational design of supramolecular biomaterials. Intricate assemblies of fibers, nets and spheres have been synthesized and characterized; however, existing approaches often lack fine control over size and morphology. In an effort to address this limitation, we have developed a system based on self-assembly of a modular subunit consisting of two α-helical peptides, which self associate to form a coiled coil, attached at their midpoints by a small organic linking group.

We found that the linker identity not only impacted the flexibility of the assemblies but linker length was important to maintaining the folding of the peptides in the subunit. Our subunit design also allowed us to examine if assembly size could be controlled by changes to coiled-coil stability through sequence mutations. Supramolecular polymer growth models show assembly size can be controlled by changes in the association affinity of the monomer. We designed, synthesized and characterized a series of coiled coils with varying folded stabilities to use in the subunits and observed that assembly size increased when the stability of the coiled coil is increased.

With the impact of the components of our self-assembling subunits characterized, we began examining if added functionality fluctuated with changes to the subunit. We developed a synthetic scheme for attaching a donor fluorophore and used a capping peptide labeled with an acceptor fluorophore to study Förster resonance energy transfer in the dimeric coiled coil and larger assemblies.

Finally, we observed that GCN4-p1, a well studied dimeric coiled coil, crystallized as either a dimer or trimer depending on the crystallization conditions. We carried out an extensive panel of solution-phase experiments to determine if the trimeric oligomerization state exists as measureable population. We found the solution conditions impact the preferred oligomerization state in the GCN4-p1 sequence.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Oshaben, Kaylynkmo35@pitt.eduKMO35
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairHorne, W. Sethhorne@pitt.edu
Committee MemberSaxena, Sunilsksaxena@pitt.edu
Committee MemberRosi, Nathanielnrosi@pitt.edu
Committee MemberDas, Subhasrdas@andrew.cmu.edu
Date: 8 June 2016
Date Type: Publication
Defense Date: 22 January 2016
Approval Date: 8 June 2016
Submission Date: 8 January 2016
Access Restriction: 1 year -- Restrict access to University of Pittsburgh for a period of 1 year.
Number of Pages: 151
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: coiled coil, peptide, supramolecular polymer, helix, biomaterial, self assembly
Date Deposited: 08 Jun 2016 15:09
Last Modified: 08 Jun 2017 05:15
URI: http://d-scholarship.pitt.edu/id/eprint/26730

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