A helical peptide (hexamer)

Both diastereomeric right-handed (P) and left-handed (M) 310-helices exist in homopeptides having twelve chiral centers at the side-chain bicyclic skeletons.
Masakazu Tanaka, Kosuke Anan, Yosuke Demizu, Masaaki Kurihara, Mitsunobu Doi, and Hiroshi Suemune
Side-chain chiral centers of amino acid and helical-screw handedness of its peptides. J. Am. Chem. Soc., 33, 3333-3333 (2005).


Skyblue ribbons: left-handed
Yellow ribbons: right-handed

drawn by iMol
@Aug. 2005

X-Ray Data Summary

formula4[C67H92N6O9, 0.5(C2H6O)]
weight 4594.0
space groupP1
Cell Crystal
a 15.765(12) Ang. description block
b 16.535(10) Ang. colour colourless
c 26.90(2) Ang. size 0.6×0.5×0.4 mm^3
α 74.22(3) deg. Dx 1.171 g/ml
β 82.32(3) deg. F(000) 2484
γ 75.39(3) deg. μ 0.078 mm^-1
volume 6514(8) Ang^3 RadiationMo Kα
Z 4
Diffrn measurementRefinement
device type Rigaku RAXIS RAPID Flack 1.3(9)
Rint 0.0530 parameters 3045
T 150 K restraints 477
θmax (deg.) 27.49 R1 0.0589
total reflections29059 wR 0.1349
reflections(obs) 14531 .gt. 2σ(I) Δρmax 0.513 e A^-3
Structure Δρmin -1.180 e A^-3
solution SHELXD Δ/σmax0.005
refinementSHELXL-97 Goodness of fit 0.885

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