Conformational behaviour of C(alpha,alpha)-diphenylglycine: folded vs. extended structures in DphiG-containing tripeptides.
The crystal structures of three fully protected tripeptides containing the Dphi g residue (C[alpha,alpha]-diphenylglycine) in the central position are reported, namely Z-Gly-Dphi g-Gly-OMe (a), Z-Gly-Dphi g-Aib-OMe (b) and Z-Aib-Dphi g-Aib-OMe (c). The molecular conformations are quite unusual because the Dphi g residue adopts a folded conformation in the 3(10)-helical region when the following residue adopts a folded conformation of opposite handedness (peptides b and c). In contrast, the Dphi g residue adopts the more frequently observed fully extended conformation when the following residue adopts a semi-extended conformation (peptide a). These findings are in agreement with the theoretical calculations on Ac-Dphi g-Aib-NHCH3 and Ac-Aib-Dphi g-NHCH3 also reported in this work.
Pavone
V
V
Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, CEINGE-Biotecnologie Avanzate, Università di Napoli Federico II, Italy.
Lombardi
A
A
Saviano
M
M
Nastri
F
F
Zaccaro
L
L
Maglio
O
O
Pedone
C
C
Omote
Y
Y
Yamanaka
Y
Y
Yamada
T
T
D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry; D011487:Protein Conformation; D017510:Protein Folding; D014961:X-Ray Diffraction
D005998:Glycine