Tackling both the player and the ball: lessons from crystallographic studies on the N-utilization substance B (NusB) from Mycobacterium tuberculosis

The N-utilization substance B (NusB) from Mycobacterium tuberculosis is an important element in a complex assembly of other proteins and ribonucleic a cid effecting transcription antitermination in this organism. The cloning a nd overexpression of the protein in E. coli, followed by the purification, crystallization, and use of selenomethionine samples to obtain phase inform ation by anomalous dispersion techniques, allows us to investigate the fine interplay of sample engineering and modification of crystallization parame ters leading to successful structure determination. Knowledge of the crysta l structure and the surface properties of the protein allows an analysis of the packing of the NusB dimers in the crystal lattice. This exercise, albe it post facto, helps to demonstrate how biophysical and functional informat ion could help 'rationalize' the course of obtaining protein crystals suita ble for structural studies. (C) 2001 Elsevier Science B.V. All rights reser ved.