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Optimal Attachment Position and Linker Length Promote Native‐like Character of Cavitand‐Based Template‐Assembled Synthetic Proteins (TASPs)
Author(s) -
Seo Emily S.,
Scott Walter R. P.,
Straus Suzana K.,
Sherman John C.
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200601784
Subject(s) - linker , cavitand , chemistry , guanidine , sequence (biology) , helix (gastropod) , template , stereochemistry , peptide , crystallography , combinatorial chemistry , glycine , peptide sequence , amino acid , biochemistry , nanotechnology , supramolecular chemistry , biology , materials science , snail , computer science , gene , crystal structure , ecology , operating system
Abstract We have designed, synthesised and characterised a series of template‐assembled de novo four‐helix bundles, each differing in the linker length between the template and the peptides. The helix is based on an earlier peptide sequence: EELLKKLEELLKKLG (first‐generation sequence), which was designed to link the hydrophilic/hydrophobic interface of the helices. Increasing or decreasing the linker length by one glycine residue had a significant effect on the structure and properties of the template‐assembled synthetic proteins (TASPs). Here, the effect of the linker length is further probed by linking the peptides closer to the hydrophobic face by using the second‐generation sequence, AEELLKKLEELLKKG, in an effort to improve the packing between the helices and to better understand the helical bundles. The peptides were synthesised with 0–4 Gly linker residues and linked onto a cavitand template. The proteins were found to be α‐helical, stable to guanidine hydrochloride (GuHCl) and to unfold cooperatively. However, their stabilities toward GuHCl, propensity to self‐aggregate and structural specificity differed. The two‐glycine variant of the second‐generation series demonstrated the highest stability and most native‐like character of all the mononeric TASPs in both the first‐ and second‐generation series. The structural specificity of this two glycine variant is comparable to that of other known native‐like de novo proteins. Molecular dynamics simulations showed that the two‐glycine variant contains helices that are tilted with respect to the cavitand template and may account for its unique properties.