GUNTHER STEINFELD, GUSTAVO SANTISO-QUINONES*
*Corresponding author
Crystallise! AG, Crystallization-X-ray-Structure, Schlieren, Switzerland

Abstract

A penta-peptide API was successfully crystallised out of the melt. The needle like crystals obtained were too small for an in-house X-ray measurement. The crystal structure was obtained using synchrotron radiation, though the absolute configuration could not be confirmed right away. Various synchrotron measurements were carried out. Optimization of different parameters like the wavelength used, various sets of scans with different orientations of the crystal, the maximum resolution obtained, among others enabled the authors to confirm the absolute structure of the compound studied. 

INTRODUCTION

According to IUPAC, a peptide is defined as: “Amides derived from two or more amino carboxylic acid molecules (the same or different) by formation of a covalent bond from the carbonyl carbon of one to the nitrogen atom of another with formal loss of water. The term is usually applied to structures formed from α-amino acids, but it includes those derived from any amino carboxylic acid” (1).

Oligopeptides (2 – 20 amino acid units), commonly known as peptides, are important building blocks of all living organisms. They are the basis for the formation of proteins (> 50 amino acid units and molecular weights > 5000 Da) and either they occur naturally or can be synthesized in the laboratory (2).

In the last three decades therapeutic peptides and proteins have shown wide applications in medicine and biotechnology and have risen in prominence as potential drugs of the future (2, 3). A recent and comprehensive study by S. Sachdeva (3) shows how important peptides are in the pharmaceutical industry. Pharmaceutical companies are very interested in the development and production of new active ingredients (API) based on ...