High-resolution diffracting crystals of intrinsically active p38α MAP kinase: a case study for low-throughput approaches

Active p38α MAP kinase mutants caused severe difficulties during crystallization. The main hindrance was found to be protein heterogeneity, which was meticulously resolved by genetically modifying the recombinant protein and optimizing the expression and purification protocols. The success in obtaining crystallizable proteins strongly emphasizes that, in certain cases, high-throughput techniques together with low-throughput approaches, with careful monitoring and analysis of the results, are essential.