The availability of whole-genome sequence data, made possible by significant advances in DNA sequencing technology, led to the emergence of structural genomics projects in the late 1990s. These projects not only significantly increased the number of 3D structures deposited in the Protein Data Bank in the last two decades, but also influenced present crystallographic strategies by introducing automation and high-throughput approaches in the structure-determination pipeline. Today, dedicated crystallization facilities, many of which are open to the general user community, routinely set up and track thousands of crystallization screening trials per day. Here, we review the current methods for high-throughput crystallization and procedures to obtain crystals suitable for X-ray diffraction studies, and we describe the crystallization pipeline implemented in the medium-scale crystallography platform at the Institut Pasteur (Paris) as an example.

International audienceA recently discovered series of inhibitors of the ATPase function of bacterial type IIA topoisomerases featuring a carboxypyrrole component led us to attempt to replace this group with a potentially bioisosteric carboxypyrazole. Accordingly, synthetic pathways to 2-(4-(1H-pyrazole-5-carboxamido)piperidin-1-yl)thiazole-5-carboxylic acids or 2-(4-(N-methyl-1H-pyrazole- 5-carboxamido)piperidin-1-yl)thiazole-5-carboxylic acids featuring an array of substituents on the pyrazole ring were explored. Unfortunately, none of the analogues made were effective on the ATPase function of Mycobacterium tuberculosis gyrase as well on the DNA supercoiling activity of the whole gyrase of M. tuberculosis and Escherichia coli. However, this work is still providing original insights in chemistry as well as in the structure–activity relationships of this series of inhibitorsUne série récente d’inhibiteurs de la fonction ATP-asique des topoisomérases bactériennes de type IIA comportant un noyau carboxypyrrole nous a conduits à tenter de remplacer celui-ci par un noyau carboxypyrazole bioisostère. Ainsi, des accès aux dérivés d’acide 2-(4-(1H-pyrazole-5-carboxamido)piperidin-1-yl)thiazole-5-carboxylique, comportant une gamme de substituants, ont été explorés. Malheureusement, aucun des analogues préparés n’a eu d’effet, que ce soit sur la fonction ATP-asique de la gyrase de Mycobacterium tuberculosis ou sur l’activité de surenroulement des gyrases de M. tuberculosis ou d’Escherichia coli. Toutefois, ce travail représente une contribution originale en ce qui concerne la chimie ou les relations structure–activité de cette série d’inhibiteurs

Figure 1. (A) Cytosine +-cytosine base pairing in i-motifs. (B) Schematic diagrams of tetramolecular (left) bimolecular (middle) and intramolecular (right) i-motifs. (C) 30×25×15 micron crystal of d(CCCT) 4 .