Synthesis of a negatively charged dibenzofuran-based beta-turn mimetic and its incorporation into the WW miniprotein-enhanced solubility without a loss of thermodynamic stability.
A versatile synthesis has been developed to functionalize the 4-(2-aminoethyl)-6-dibenzofuran propionic acid residue (1a) at the 2 and 8 positions with a variety of different substructures. The unfunctionalized version of this peptidomimetic (1a) is known to facilitate beta-hairpin formation in a variety of small peptides and proteins in aqueous solution when incorporated in place of the i + 1 and i + 2 residues of a beta-turn. In this study, we append propionate substituents on 1a at the 2 and 8 positions to successfully overcome solubility problems encountered with the incorporation of 1a in place of the i + 1 and i + 2 residues of the beta-turn in loop 1 of the WW domain. The thermodynamic stability of several WW domain analogues incorporating residues 1a and 1b was compared to that of the wild-type sequence revealing comparable DeltaG(H(2)O) unfolding values at 4 degrees C ranging from 3 to 3.6 kcal/mol. WW domains incorporating residue 1b exhibit improved solubility (exceeding 100 microM) and resistance to aggregation without compromising thermodynamic stability.
D000595:Amino Acid Sequence; D001572:Benzofurans / Q000138:chemical synthesis / Q000737:chemistry*; D001703:Biophysics / Q000379:methods; D008958:Models, Molecular; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D010446:Peptide Fragments / Q000737:chemistry; D019696:Peptidylprolyl Isomerase / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013816:Thermodynamics
D001572:Benzofurans; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D010446:Peptide Fragments; D019696:Peptidylprolyl Isomerase