Crystal Structure and Conformation of Short Linear Peptides: Part I: L-Phenylalanyl-Glycyl-Glycine

C13H17N3O4, Mr = 279.30, orthorhombic, P212121, a = 5.743(2), b = 16.072(10), c = 15.317(10)A, V = 1347(1)A3, Z = 4, Dx = 1.38 g. cm−3, MoKα, λ = 0.71069 A, μ = 1.12 cm−1, F(000) = 592, T = 291K, R = 0.036 for 1372 observed reflections. The molecule partly assumes a 310-helical conformation. The side chain of the Phe residue has an unusual conformation characterized by angles X1 = 176° and X21 = 53°.