Selection of a buried salt bridge by phage display

Towards identifying preferred interaction partners of fluorinated amino acids within the hydrophobic environment of a dimeric coiled coil peptide

“…The VPE peptides that were selected by screening this library for the VPK wild type, and the DfeGly-, DfpGly-and TfeGlysubstituted analogues, show little variance and preferably follow the pattern Leu( 12)Ile( 16)Leu (19). Except for position g¢ 15 , this peptide sequence in principle matches those which were selected from the first library (amino acid positions d¢ 12 , g¢ 15 , a¢ 16 and d¢ 19 randomized).…”

“…The amino acids selected for the variable positions in principle follow the pattern Leu( 12)Leu( 15)Ile( 16 This journal is © The Royal Society of Chemistry 2010 selection of this amino acid. 20 The occurrence of tyrosine in position g¢ 15 seems to be more favourable because of the stronger steric hindrance of the aromatic side chain in position d¢ 19 . As exclusively hydrophobic amino acids were selected in position g¢ 15 , a VPE variant bearing leucine in both d¢ positions as well as in position g¢ 15 (VPE-L 15 I 16 ) is also expected to form a favourable binding partner for the VPK wild type and for the fluorinated VPK variants.…”

“…The additional hydrophobic amino acid position stabilizes the coiled coil structure, which basically relies on hydrophobic interactions and reduces the sensitivity for changes in position a 16 . To avoid this effect and to check if any differences in the selection results can be detected, a second library was constructed in which position g¢ 15 remained unmodified and solely the hydrophobic core positions d¢ 12 , a¢ 16 and d¢ 19 were randomized.…”

“…16 Based on the same peptide model system, we recently described a phage display 17, 18 -based screening strategy that allows the determination of preferred interactions within the hydrophobic core. 19 Here, we describe the use of this screening system to investigate the interaction possibilities of fluorinated amino acids within the hydrophobic environment of the coiled coil interaction domain. The predominant goal of this study was to determine the best binding partners for coiled coil strands bearing fluorinated amino acids.…”

Design and Characterization of Endosomal‐pH‐Responsive Coiled Coils for Constructing an Artificial Membrane Fusion System

“…On the other hand, AP-LZA C H T U N G T R E N N U N G (EH8), with the salt-bridge pair at the directly opposed position, has less helical content because of the limited distance between the charged side chains, as had been reported previously. [18] Chemical-and thermal-denaturation experiments of the designed polypeptides were performed to gain insights into the stability of their coiled coil structures (Table 1). The stabilities of AP-LZ(LL) at pH 7.0 (DG 0 = 10.14 AE 0.14 kcal per mole coiled coil unit, T m = 54 8C) and at pH 5.0 (DG 0 = 10.10 AE 0.08 kcal per mole per coiled coil unit, T m = 55 8C) are comparable to those of the GCN4-pl coiled coil dimer.…”