Krause J A, Baures P W, Eggleston D S
SmithKline Beecham Pharmaceuticals, Department of Physical and Structural Chemistry, King of Prussia, PA 19406.
Acta Crystallogr B. 1993 Feb 1;49 ( Pt 1):123-30. doi: 10.1107/s0108768192006207.
L-Leu-L-Tyr, (I), C15H22N2O4, M(r) = 294.35, crystallizes from MeOH/5% dimethyl sulfoxide in the orthorhombic space group P2(1)2(1)2(1). a = 5.644 (1), b = 12.094 (3), c = 22.548 (4) A, V = 1539.0 (5) A3, Z = 4, Dx = 1.270 g cm-3, Cu K alpha, lambda = 1.54184 A, mu = 7.228 cm-1, F(000) = 632, T = 173 K, final R (on F) = 0.033 for 1347 observations with I > or = 2 sigma (I). (I) crystallizes as a zwitterion with the N-terminus protonated and the C-terminus ionized. The peptide backbone adopts a distorted trans antiparallel beta pleated-sheet conformation, with principal torsion angles psi 1 = 163.7 (2), omega 1 = 158.7 (2), phi 2 = -110.9 (3) and psi 2 = 141.4 (2)degrees. The leucyl residue is in the g-(tg-) conformation while the tyrosyl residue adopts the g- conformation, with the phenol ring twisted from the low-energy perpendicular position. Gly-D,L-Met.p-toluenesulfonate, (II), C7H15N2O3S+.C7H7O3S-, M(r) = 378.47, crystallizes from MeOH/EtOAc in the orthorhombic space group Pbca. a = 33.642 (4), b = 15.951 (1), c = 6.785 (1) A, V = 3641.0 (4) A3, Z = 8, Dx = 1.381 g cm-3, Cu K alpha, lambda = 1.54184 A, mu = 28.865 cm-1, F(000) = 1600, T = 223 K, final R (on F) = 0.055 for 1669 observations with I > or = 3 sigma (I). Gly-D,L-Met exists as a cation with the N- and C-termini protonated, the p-toluenesulfonate being the counterion.(ABSTRACT TRUNCATED AT 250 WORDS)
L-亮氨酰-L-酪氨酸（I），化学式为C15H22N2O4，相对分子质量M(r)=294.35，从甲醇/5%二甲基亚砜中结晶，属于正交晶系空间群P2(1)2(1)2(1)。a = 5.644 (1)，b = 12.094 (3)，c = 22.548 (4) Å，V = 1539.0 (5) ų，Z = 4，Dx = 1.270 g cm⁻³，铜Kα射线，λ = 1.54184 Å，μ = 7.228 cm⁻¹，F(000) = 632，T = 173 K，对于1347个I≥2σ(I)的观测值，最终R（基于F）= 0.033。（I）以两性离子形式结晶，N端质子化，C端离子化。肽主链呈扭曲的反平行β折叠构象，主要扭转角ψ1 = 163.7 (2)，ω1 = 158.7 (2)，φ2 = -110.9 (3)，ψ2 = 141.4 (2)°。亮氨酰残基处于g-(tg-)构象，而酪氨酰残基采用g-构象，酚环从低能量垂直位置扭曲。甘氨酰-D,L-蛋氨酸对甲苯磺酸盐（II），化学式为C7H15N2O3S⁺·C7H7O3S⁻，相对分子质量M(r)=378.47，从甲醇/乙酸乙酯中结晶，属于正交晶系空间群Pbca。a = 33.642 (4)，b = 15.951 (1)，c = 6.785 (1) Å，V = 3641.0 (4) ų，Z = 8，Dx = 1.381 g cm⁻³，铜Kα射线，λ = 1.54184 Å，μ = 28.865 cm⁻¹，F(000) = 1600，T = 223 K，对于1669个I≥3σ(I)的观测值，最终R（基于F）= 0.055。甘氨酰-D,L-蛋氨酸以阳离子形式存在，N端和C端均质子化，对甲苯磺酸盐为抗衡离子。（摘要截断于250字）
