Naslov
Structure and molecular modelling of protected dipeptide fragmet (Boc-Phe-Leu-Obzl) of enkephalin

Autori
Antolić, Snježana ; Teichert, Michael ; Sheldrick, George ; Kojić-Prodić, Biserka ; Čudić, Mare ; Horvat, Štefica

Izvornik
Acta crystallographica. Section B, Structural science (0108-7681) 55 (1999), 6; 975-984

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
protected dipeptide enkephalin fragment ; X-ray structure ; molecular modelling

Sažetak
The conformational characteristics of a flexible totally protected C-terminal dipeptide fragment (Boc–Phe–Leu–OBzl) of enkephalin are studied using X-ray data, molecular modelling and data retrieved from the Cambridge Structural Database. The dipeptide crystallizes with seven conformers in the asymmetric unit. C27H36N2O5, T = 133 K, monoclinic, P21, a = 13.706 (3), b = 22.800 (3), c = 30.674 (5) Å, β = 97.15 (3)°, V = 9511 (3) Å3, Z = 14, Dc = 1.145 Mg m−3. Six of the seven molecules exhibit folded conformations with hydrophobic groups disposed at the opposite side of the peptide backbone. The characteristic Φ1 and Ψ1 angles of the Phe residue and Φ2 of the Leu fragment are in the allowed region defined in the Ramachandran diagram. However, they do not belong to the family of the lowest energy conformations. In the crystal, molecules are interconnected via N—H⋯O hydrogen bonds of peptide groups forming an infinite sheet similar to a parallel β-sheet. Molecular dynamics simulations performed in vacuo reproduce the conformers and rotamers detected in the solid state.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA