@PhdThesis{diss_mods_00021275,
  author = 	{Lipfert, Matthias},
  title = 	{Design of a Stabilizing and Switching Module for alpha-Helical Peptides},
  year = 	{2017},
  publisher = 	{Christian-Albrechts-Universit{\"a}t zu Kiel},
  address = 	{Kiel},
  keywords = 	{Antifreeze Protein; Trp-cage; Switching; Stabilizing short peptides; Antigefrierprotein; Schalten; Stabilisieren kurzer Peptide},
  abstract = 	{In this work, the concept of a modular approach to stabilize and switch the structure of $\alpha$-helical proteins and peptides was investigated. To achieve such, we designed a fusion protein which consists of two parts. The first part, an independent protein module, comprises a highly stable helical fold and the possibility to incorporate a light responsive unit for manipulation of the structure. The second part consists of a peptide sequence with a structure-dependent activity.
We used the 20 amino acid long Trp-cage miniprotein as basis for the stabilizing and switching module. Its tertiary structure consists of an eight amino acid long N-terminal $\alpha$-helix, whose fold is induced by encapsulation of the eponymous tryptophan side chain by several C-terminal residues. This results in a very stable tertiary fold of the module. In order to introduce switchability into the miniprotein, we cross-linked the Trp-cage with a photo responsive linker. In this work, we used N-hydroxysuccinimide esters (NHS) as reactive groups for the cross-linking, which are reactive towards primary amines (lysine residues), and azobenzene as the scaffold for a switchable linker. 
In the second part of this work, one repeat of the $\alpha$-helical antifreeze protein AFP "Type 1 HPLC6" was fused with the Trp-cage module using a chimera strategy. In order to combine and correlate the secondary structure of the proteins, the sequences were overlapped, resulting in a chimera protein. This protein comprises at the N-terminus the sequence of the antifreeze protein, followed by a chimera region with a combination of both sequences, and is completed by the C-terminal sequence of the Trp-cage. The junction of the sequences is possible in four different ways altering the orientation of the active side of the antifreeze protein relative to the tertiary structure of the Trp-cage. All four variants were spectroscopically characterized in order to ascertain their structure. Furthermore, the activity of the four chimera proteins was determined by observing the ice crystal growth in presence of the proteins.},
  url = 	{https://macau.uni-kiel.de/receive/diss_mods_00021275},
  file = 	{:https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00007187/20170710ML.pdf:PDF},
  language = 	{en}
}