Crystallization and structural studies of n-benzyloxycarbonyl-L-tyrosine-L-glycine-ethyl ester (Z-Tyr-Gly-OEt) by A. Nallini, K. Saraboji, M. N. Ponnuswamy, and S. B. Katti

Crystal Research and Technology

Cryst. Res. Technol. 39, 279 (2004) - Abstract -

Crystallization and structural studies of n-benzyloxycarbonyl-L-tyrosine-L-glycine-ethyl ester (Z-Tyr-Gly-OEt)

A. Nallini, K. Saraboji, M. N. Ponnuswamy, and S. B. Katti*

Department of Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai –600 025, India
*Division of Biopolymers, Central Drug Research Institute, Lucknow –226 001, India

Keywords	tyrosine, peptide, crystallization, crystal structure, conformation, hydrogen bonding
PACS	61.66.Hq
DOI	10.1002/crat.200310183

It is axiomatic that efficient crystal production reflects upon the quality of structure. An empirical relation for mass proportions of two solvents in crystallization of Z-Tyr-Gly-OEt shows a linear relationship. The dipeptide crystallizes in orthorhombic space group P2₁2₁2₁, with cell parameters a=5.0680(1)Å, b=13.8650(1)Å and c=28.2630(1)Å, Z=4, D_calc= 1.339Mg/m³, μ=0.820mm^-1, F₀₀₀=848, CuKα = 1.5418Å. The structure was solved by direct methods and final R1 and wR2 are 0.444 and 0.1276, respectively. The structure analysis reveals the trans conformation of the peptide unit with ω=-178.2(5)°, implying only a slight deviation from planarity. The torsion angles at glycine are characteristic of left-handed poly glycine II helices. A number of N-H…O, O-H…O and C-H…O hydrogen bondings play a role in stabilizing the molecules within unit cell.

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