title: Optimal attachment position and linker length promote native-like character of cavitand-based template-assembled synthetic proteins (TASPs).
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 alpha-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.
authors.affiliation: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
authors.forename: Emily S
authors.initials: ES
authors.lastname: Seo
authors.forename: Walter R P
authors.initials: WR
authors.lastname: Scott
authors.forename: Suzana K
authors.initials: SK
authors.lastname: Straus
authors.forename: John C
authors.initials: JC
authors.lastname: Sherman
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D003198:Computer Simulation; D004988:Ethers, Cyclic / Q000737:chemistry; D019791:Guanidine / Q000737:chemistry / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011506:Proteins / Q000138:chemical synthesis* / Q000737:chemistry; D012118:Resorcinols / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: D004988:Ethers, Cyclic; D011506:Proteins; D012118:Resorcinols; C442939:cavitand; D019791:Guanidine