12/10-Helical β-Peptide with Dynamic Folding Propensity: Coexistence of Right- and Left-Handed Helices in an Enantiomeric Foldamer.
We present the first examples of atomic-resolution crystal data for the β-peptide 12/10-helix from oligomers of cis-2-aminocyclohexane carboxylic acid (cis-ACHC) with alternating chirality. The local conformations of two enantiomeric cis-ACHC dimer units suggested that a chiral β-peptide may adopt both right-handed and left-handed helical conformations in solution. To probe the conformational behavior of 12/10-helical β-peptides, the two reference helices with a single handedness were synthesized with a more rigidified cis-ACHC derivative. Comparison with these reference helices at low temperature revealed that a chiral cis-ACHC oligomer with alternating chirality indeed displays 12/10-helical conformations with both handedness that equilibrate rapidly in solution. This is a very rare example of chiral oligomers with helix inversion ability. The 12/10-helical backbone should be a valuable addition to potential scaffolds for applications involving helices with dynamic folding propensity.
Department of Chemistry, Yonsei University , Seoul 03722, Korea.
Seonho
S
Shin
Department of Chemistry, Yonsei University , Seoul 03722, Korea.
Mihye
M
Lee
Department of Chemistry, University of Wisconsin , Madison, Wisconsin 53706, United States.
Ilia A
IA
Guzei
Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea.
Young Kee
YK
Kang
Department of Chemistry, Yonsei University , Seoul 03722, Korea.
Soo Hyuk
SH
Choi
D018360:Crystallography, X-Ray; D003510:Cyclohexanes / Q000737:chemistry; D008958:Models, Molecular; D009842:Oligopeptides / Q000737:chemistry*; D000072756:Protein Conformation, alpha-Helical; D000072757:Protein Conformation, beta-Strand; D017510:Protein Folding; D055503:Protein Multimerization; D013237:Stereoisomerism
D003510:Cyclohexanes; D009842:Oligopeptides; C506365:Cyclohexane